A composition for treating male erectile dysfunction and its use

Abstract

The present application belongs to the technical field of biological medicine, and particularly relates to a composition for treating male erectile dysfunction and application thereof. The oyster polypeptide is prepared by oyster protease hydrolysis, and the oyster polypeptide can effectively promote the proliferation of testicular interstitial cells, enhance and improve sexual desire and sexual behavior, has certain clinical application value, and has the advantages of simple preparation, easy absorption and the like, and is easy to popularize and apply.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological medicine, and particularly relates to a composition for treating male erectile dysfunction and application thereof. BACKGROUND

[0002] Erectile dysfunction (ED) refers to the persistent inability to achieve or maintain sufficient erectile rigidity to complete satisfactory sexual intercourse. It is more common in middle-aged and elderly men. With the development of society and the change of lifestyle, work pressure and other factors, the incidence tends to be younger and younger, and there are many patients under the age of 20 in male clinics. It seriously affects the mental and physical health of men, causes disharmony in sexual partner relationships, and affects the stability of families and society.

[0003] Erectile function is the result of the synergistic action of nerves, blood vessels, and endocrine factors on the hemodynamics of the cavernous body of the penis. First, a certain sexual stimulus is needed. Non-adrenal non-cholinergic neurons secrete nitric oxide (NO) and other neurotransmitters. Activate guanylate cyclase to convert it into the second messenger cyclic guanosine monophosphate (cGMP) to increase the intracellular cGMP concentration, reduce the intracellular Ca 2+ concentration, dilate the cavernous body smooth muscle, expand the cavernous body sinus, increase arterial blood flow, and expand the cavernous body volume. The white membrane of the cavernous body is passively elongated, the white membrane under the backflow vein is compressed, the venous blood flow is blocked, and the penis is enlarged, thickened and hardened. Generally, erectile dysfunction is divided into three categories according to the cause: organic ED, psychological ED and mixed ED. Among them, organic ED includes vascular (arterial and venous), neurological and endocrine. Erectile function is a local manifestation of overall health. Sexual desire, neurotransmitters, sex hormone levels, blood vessels and hemodynamics, and cavernous body structure all play a crucial role in erectile function, so any pathology can lead to ED. In addition, obesity, especially abdominal obesity, diabetes, hypertension, cardiovascular disease and other psychological diseases such as depression can also easily cause sexual dysfunction in middle-aged and elderly men.

[0004] The first-line treatment for ED includes oral drugs, psychological behavior therapy, vacuum negative pressure erection devices and constriction rings, etc. Among them, oral drugs are convenient to use and more easily accepted by most patients. Current oral drugs for treatment include phosphodiesterase type 5 inhibitors (PED5i), apomorphine, yohimbine, testosterone preparations, etc. However, the above drugs as chemical prostheses are only used to induce penile erection once, and have different degrees of side effects, such as flushing, headache, hypotension, local pain, persistent penile erection, etc. Therefore, safe and effective drugs to enhance the natural erectile function of the human body need to be developed, and have important significance and value.

[0005] Oyster is the world's largest farmed shellfish, and one of the four largest farmed shellfish in China, is a very precious marine mollusk. Oyster is rich in protein and glycogen, and also rich in various vitamins and trace elements such as copper, iron, zinc and iodine, especially rich in taurine, and has high nutritional value. As a resource of marine health food and marine medicine, oyster shows great development potential. Recent scientific research shows that bioactive peptides have special physiological activities, mainly in immune activity, antihypertensive, antilipid, growth-promoting activity, tumor inhibitory activity, etc. It is these active effects that show that bioactive peptides have great application prospects in food and pharmaceutical industries. It has been reported that deer horn polypeptide can significantly increase the content of interstitial cell stimulating hormone in the plasma and adrenal gland cell culture fluid of male mice, and oyster polypeptide and ginseng oligopeptide can improve the sexual function of mice and significantly increase the content of testosterone in the plasma of male mice. SUMMARY

[0006] In view of the prior art, the purpose of the present application is to provide an oyster polypeptide for treating male erectile dysfunction and its application. Specifically, the oyster polypeptide provided by the present application can promote the synthesis and secretion of NO and testosterone, promote the proliferation of Leydig cells, and enhance the improvement of sexual desire and sexual behavior. In addition, the oyster polypeptide provided by the present application has no toxicity and no side effects, and has the advantages of simple preparation, easy absorption, etc., and can be used for preparing health care products or drugs.

[0007] The present application first provides an oyster polypeptide, characterized in that the amino acid sequence thereof is shown as SEQ ID NO: 1.

[0008] In some embodiments, the oyster polypeptide can promote the secretion of NO and testosterone.

[0009] In some embodiments, the oyster polypeptide can promote the proliferation of Leydig cells.

[0010] In some embodiments, the oyster polypeptide can improve sexual desire and sexual behavior.

[0011] Another aspect of the present application also provides a nucleic acid molecule encoding the oyster polypeptide of the present application.

[0012] Another aspect of the present application also provides a vector comprising the nucleic acid molecule of the present application.

[0013] Another aspect of the present application also provides an isolated host cell comprising the oyster polypeptide of the present application, the nucleic acid molecule of the present application, or the vector of the present application.

[0014] Another aspect of the present application also provides the use of the oyster polypeptide for preparing health care products or drugs for treating male erectile dysfunction.

[0015] Another aspect of the present application provides a pharmaceutical composition comprising an effective amount of the oyster polypeptide, the amino acid sequence of which is shown as SEQ ID NO: 1.

[0016] The oyster polypeptide or the pharmaceutical composition comprising the oyster polypeptide of the present application is administered in the form of a lyophilized powder.

[0017] In some embodiments, the oyster polypeptide or the pharmaceutical composition comprising the oyster polypeptide of the present application can be further used in combination with other drugs for treating erectile dysfunction.

[0018] In some embodiments, the drugs for treating erectile dysfunction can be selected from sildenafil, tadalafil, vardenafil, avanafil, dapoxetine hydrochloride, Bushenning tablets, testosterone hormone, etc.

[0019] Advantages

[0020] The present application extracts and prepares an active polypeptide from oysters, which effectively promotes the synthesis and secretion of NO and testosterone, promotes the proliferation of Leydig cells, enhances and improves sexual desire and behavior, and has certain clinical application value. In addition, the polypeptide 6G-33 provided by the present application is easy to synthesize, low in cost, and easy to popularize and apply. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The results shown are the promotion of testosterone secretion by mouse Leydig cells after G6-33 polypeptide treatment.

[0022] Figure 2 The results shown are the increase in serum testosterone content of mice after G6-33 polypeptide treatment.

[0023] Figure 3 The results shown are the increase in serum NO content of mice after G6-33 polypeptide treatment.

[0024] Figure 4 The results shown are the changes in the organ index of the sexual organs of mice after G6-33 polypeptide treatment. DETAILED DESCRIPTION

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as would be understood by one of ordinary skill in the art to which this application belongs.

[0026] Except in the operating and comparative examples, or where otherwise indicated, all numbers used herein to express quantities, reaction conditions, or concentrations should be understood as being modified in all instances by the term "about". The term "about", when used in conjunction with a percentage, can mean ± 1%.

[0027] In some embodiments, the pharmaceutical compositions provided herein comprise about 1 pg to about 2000 mg of an active polypeptide described herein (e.g., a polypeptide component, which in some embodiments can be a single polypeptide), optionally wherein the pharmaceutical composition comprises about 1 pg to about 1000 mg, about 1 pg to about 500 mg, about 1 pg to about 400 mg, about 1 pg to about 300 mg, about 1 pg to about 200 mg, about 1 pg to about 100 mg, about 1 pg to about 50 mg, about 1 pg to about 25 mg, about 1 pg to about 20 mg, about 1 pg to about 15 mg, about 1 pg to about 10 mg, about 1 pg to about 5 mg, about 1 pg to about 1 mg, about 1 pg to about 500 pg, about 1 pg to about 250 pg, about 1 pg to about 200 pg, about 1 pg to about 150 pg, about 1 pg to about 100 pg, about 1 pg to about 50 pg, about 1 mg to about 1000 mg, about 1 mg to about 500 mg, about 1 mg to about 400 mg, about 1 mg to about 300 mg, about 1 mg to about 200 mg, about 1 mg to about 100 mg, about 1 mg to about 50 mg, about 1 mg to about 25 mg of an active polypeptide described herein (e.g., a polypeptide component, which in some embodiments can be a single polypeptide).

[0028] As used herein, “treatment” or “treating” or “amelioration” are used interchangeably herein. These terms refer to an approach for obtaining beneficial or desired results, including but not limited to therapeutic benefit and / or prophylactic benefit.

[0029] In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of “or” means “and / or” unless stated otherwise. Furthermore, the use of the term “including” as well as other forms such as “includes” and “included” is not limiting. Also, terms such as “element” or “component” encompass both elements and components including a single unit and elements and components that comprise more than one subunit unless specifically stated otherwise. Additionally, the use of the term “part” can include a portion or the whole of an item. Throughout this specification, unless the context requires otherwise, the word “comprise,” or variations such as “comprises” or “comprising,” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0030] The term "therapeutically effective amount" refers to an amount that produces the desired effect for which it is administered. In some embodiments, the term refers to an amount that is sufficient, when administered to a population suffering from or susceptible to a disease, disorder, and / or condition, in accordance with a therapeutic dosing regimen, to treat the disease, disorder, and / or condition. In some embodiments, a therapeutically effective amount is an amount that reduces the incidence and / or severity of, and / or delays onset of, one or more symptoms of a disease, disorder, and / or condition. Those of ordinary skill in the art will understand that a therapeutically effective amount does not necessarily result in successful treatment in every particular treated individual. Rather, a therapeutically effective amount can be an amount that provides a particular desired pharmacological response in a significant number of subjects when administered to patients in need of such treatment. In some embodiments, reference to a therapeutically effective amount can be a reference to an amount as measured in one or more particular tissues (e.g., tissues affected by a disease, disorder, or condition) or fluids (e.g., blood, saliva, serum, sweat, tears, urine, etc.). Those of ordinary skill in the art will understand that, in some embodiments, a particular agent or therapy can be formulated and / or administered in a single dose of a therapeutically effective amount. In some embodiments, a therapeutically effective agent can be formulated and / or administered in multiple doses, e.g., as part of a dosing regimen.

[0031] The pharmaceutical composition of the present application further comprises a pharmaceutically acceptable carrier.

[0032] Further, the pharmaceutical compositions of the present application can be in oral dosage forms. Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In these solid dosage forms, the active polypeptide is mixed with at least one conventional inert diluent such as sodium citrate or dicalcium phosphate or with such other ingredients as binders, (a) fillers or solubilizers, such as starches, lactose, sucrose, glucose, mannitol, and silicic acid; (b) humectants, such as hydroxymethylcellulose, alginic acid, gelatin, polyvinylpyrrolidone, sucrose and acacia; (c) moisturizing agents, such as glycerol; (d) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain complex silicates and sodium carbonate; (e) solution retarders, such as paraffin; (f) absoφtion accelerators, such as quaternary ammonium compounds; (g) moistening agents, such as lecithin and

[0033] The provided formulations can include a lyoprotectant, for example, which can be selected from the group consisting of sucrose, lactose, trehalose, dextran, erythritol, arabitol, xylitol, sorbitol, maltose, lactulose, maltitol, glucitol, lactitol, isomaltulose, and mannitol; an amino acid, for example, arginine or histidine or proline or glycine; a kosmotropic salt, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol), or poly(propylene glycol); gelatin, dextrin, modified starch, carboxymethylcellulose, and combinations thereof.

[0034] Alternatively or additionally, in some embodiments, the provided formulation can comprise a penetration enhancer, for example, it can be selected from the group consisting of bile salts, such as trihydroxy salt cholic acid sodium, glycocholic acid sodium, taurocholic acid sodium and dihydroxy salts, deoxycholic acid sodium, glycodeoxycholic acid sodium, taurodeoxycholic acid sodium; fatty acids, their salts and esters, such as, for example, oleic acid, lauric acid, cod liver extract, sodium laurate, sodium caprate, glycerol monostearate, diethylene glycol monoethyl ether and various sucrose fatty acid esters, medium chain fatty acid glycerides, polycaprolactone eoma-3 fatty acids, lecithin (phosphatidylcholine), lysophosphatidylcholine; surfactants, such as sodium dodecyl (lauryl) sulfate, polysorbate (polysorbate 80), lauryl ether, brijs and benzalkonium chloride; complexing agents, such as cyclodextrins, dextran sulfate, dextran sulfate, sodium ethylenediaminetetraacetate; complexing agents, such as cyclodextrins, dextran sulfate, dextran sulfate, sodium ethylenediaminetetraacetate, cosolvents, such as ethanol and propylene glycol, a combination of 1% oleic acid and 5% / 10% polyethylene glycol 200, a combination of 2% glyceryl monolaurate and 40% alcohol, sodium caprate and alcohol or propylene glycol, a combination of 10% lauric acid in propylene glycol, polyoxyethylene, 2,3-lauryl ether, menthol, sodium caprate, sodium caprylate, sodium glycodeoxycholate, ethylene glycol; polysaccharides, such as chitosan and chitosan glutamate; and others, such as aprotinin, benzalkonium chloride, cetylpyridinium chloride, cetyltrimethylammonium bromide, sodium salicylate, lysophosphatidylcholine, methoxy salicylate, hydroxymethyl salicylate, sodium edta, sulfoxides, various alkyl glycosides, ethylenediaminetetraacetic acid (edta), tartaric acid; lyotropic salts, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol) or poly(propylene glycol); gelatin, dextrin, modified starch, carboxymethyl cellulose and combinations thereof.

[0035] Optionally or additionally, in some embodiments, the provided formulation can include an absorption enhancer, for example, which can be selected from a surfactant, a cholate, a glyceride, a salicylate, a bile salt, a chelating agent, sodium caprate, a salt of capric acid, and others including N-(5-chlorosalicyloyl)-8- aminooctanoic acid (5-CNAC), 4-((4-chloro-2-hydroxybenzoyl))-amino)butyric acid (4- CNAB), and N-(8-(2-hydroxybenzoyl))-amino)octanoic acid, also known as sodium nicosulfate (SNAC, octanoic acid, C8, castor oil, medium-chain, acylcarnitine, EDTA, glycerol monolaurate, bovine P- casein, tocopherol succinate ethylene glycol chitosan conjugate, lecithin, glycerol monostearate (GMS), chitosan and alginate, PLGA, silicon dioxide, stearic acid, oleic acid, hydrogenated castor oil, and trimyristin, etoposide phosphate, sulindac, enalapril maleate, ramipril, olmesartan medoxomil, valacyclovir, midodrine, gabapentin enacarbil, sulfasalazine, or alternatively or additionally, in some embodiments, the provided formulation can include a mucosal bioadhesive agent, for example, which can be selected from sucrose, lactose, trehalose, dextran, erythritol, arabinose, xylitol, sorbitol, maltose, lactulose, maltulose, glucitol, maltitol, lactitol, isomaltulose, and mannitol; an amino acid, for example, arginine or histidine or proline or glycine; a lyotropic salt, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol), or poly(propylene glycol);Gelatin, dextrin, modified starch, carboxymethyl cellulose and combinations thereof, mucoadhesive systems, such as mucoadhesive systems from nature, such as gelatin, agarose, chitosan, hyaluronic acid and synthetic polymers, such as polyvinylpyrrolidone (PVP), polyacrylate, polyvinyl alcohol, sodium carboxymethyl cellulose (SCMC) and pectin, all anionic polymers, chitosan (cationic) and hydroxypropyl methylcellulose (HPMC) as non-ionic polymer, polyacrylic acid (PAA) derivatives (CP 934, CP 940, PCP), 15% CMC and 35% CP, copolymer of acrylic acid and poly(ethylene glycol) monomethyl ether monomethacrylate (PEG MM), eudragit l NE 40D is a neutral poly(ethyl acrylate methacrylate), hydrophilic polymers such as, methocel K4M, methocel K15M, SCMC 400, Cekol 700, Cekol 10000, CP 934P, CP 971P and CP 974P, carboxyvinyl polymers and triethanolamine, HPC (hydroxypropyl cellulose), CP (carbopol 934P), carbopol (CP) Ex-55 CMC (sodium carboxymethyl cellulose), HPMC (hydroxypropyl methylcellulose), HEC (hydroxyethyl cellulose), PIP [poly(isoprene)], PIB [poly(isobutylene)], xanthan gum, locust bean gum, pectin, polycarbophil, benzyl ester, hydroxyethyl cellulose, poly(acrylic acid), poly(acrylic acid-co-acrylamide), poly(acrylic acid-co-methyl methacrylate), poly(acrylic acid-co-butyl acrylate), (bioadhesive polymer blend of CP and PIB), formulations consisting of PVP, cetylpyridinium chloride (as stabilizer), chitosan chloride, polyethylene oxide, polymethylvinyl ether / maleic anhydride (PME / MA) and tragacanth gum, polyethylene glycol monomethyl ether monomethacrylate, drum-dried waxy maize starch (DDWM), carbopol 974P and sodium stearyl fumarate and cellulose derivatives; hydrogels - acrylic acid (polar) and butyl acrylate (non-polar) and combinations thereof.

[0036] In addition to these inert diluents, the compositions can also include adjuvants, such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

[0037] In addition to the active polypeptide, the suspension can contain suspending agents such as ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide gel, and agar-agar, or mixtures of these substances.

[0038] Compositions for parenteral injection can include physiologically acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions and sterile powders for reconstitution into sterile injectable solutions or dispersions. Suitable aqueous and nonaqueous carriers, diluents, solvents or excipients include water, ethanol, polyols and suitable mixtures thereof.

[0039] Dosage forms of the polypeptides of the present application for topical administration include powders, patches, sprays, and inhalers. The active ingredients are mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or necessary propellants as can be required. It will be appreciated that formulatory agents can be present as components of parent compositions and can be chosen with due regard for the particular

[0040] The pharmaceutical compositions of the present application are formulated to have a pH of 5.5 to 7.5. In one embodiment, the pH of the aqueous medium can be adjusted by low concentrations of suitable biocompatible buffering ingredients, non-limiting examples of which are tromethamine, sodium and sodium bicarbonate, and sodium and disodium phosphate.

[0041] The compositions of the present application can be administered daily or intermittently, and the frequency of administration can be once daily or 2 to 3 times daily. If each of the two active ingredients is a single formulation, their frequency of administration can be the same or different from each other. In addition, the compositions of the present application can be used alone or in combination with other drugs for treating erectile dysfunction. In view of all the above factors, it is important to administer at the lowest dose to achieve the best efficacy without side effects, which can be easily determined by one skilled in the art. In some embodiments, the dosing regimen is repeated, e.g., once, twice, three times, or more; for example, for the remainder of the life of the individual in need.

[0042] The present application is further described in detail by means of the following drawings and examples, but is not limited in any way by the following drawings and examples, and any modification or improvement made based on the teachings of the present application falls within the scope of the present application.

[0043] Example 1. Preparation of oyster polypeptide

[0044] The soft part of oysters was taken out, washed to remove mud and sand, and then drained. The oyster meat was crushed and homogenized by a high-speed homogenizer at a solid-to-liquid ratio of 1:3 (w / v). Flavourzyme was added at 1.3% under the conditions of natural pH and 47°C for enzymatic hydrolysis for 5 hours. After the enzymatic hydrolysis was completed, the enzyme was inactivated by boiling water bath for 10 minutes, and then quickly cooled to room temperature. The supernatant was obtained by centrifugation at 8000 r / min for 20 minutes at 4°C, and then concentrated.

[0045] The enzyme hydrolysate of oyster was fractionated by using Milipore 200 mL stirring ultrafiltration equipment and its matched 10 ku and 5 ku ultrafiltration membranes. The inlet pressure was controlled at 50 psi, and three ultrafiltration components, OS1 (<5 ku), OS2 (5-10 ku) and OS3 (>10 ku) were obtained. Each component was collected and freeze-dried for standby use.

[0046] The effect of each protein component on the proliferation activity of mouse testicular interstitial cells (TM3 cells) was detected by MTT method. Specifically, TM3 cells were cultured in DMEM / F-12 medium (92.5%) supplemented with 5% (V / V) horse serum and 2.5% (V / V) high-quality fetal bovine serum. The cells were cultured in a cell incubator under the conditions of 5% CO2, 95% humidity and 37°C. 6000 cells were added to each well of a 96-well culture plate for plating, and after 12 h of culture, the cells were treated with different concentrations (0.125, 0.25, 0.5, 1, 2 mg / mL) of ultrafiltration components (<5, 5-10 and >10 ku), and cultured for 24 h. After the end of culture, 20 μL of MTT reagent was added to each well, and the culture plate was incubated for 4 h. The supernatant was carefully aspirated, 100 μL of DMSO was added to each well, and then the culture plate was gently shaken for 10 min. The absorbance of the supernatant was measured at 570 nm by an enzyme-labeled instrument.

[0047] The OS1 (<5 ku) component with the strongest TM3 cell proliferation activity was further separated and purified. Specifically, Sephadex G25 gel was fully swollen in distilled water at room temperature for 24 h, and a 1.6 cm x 50 cm chromatography column was packed with the gel. The gel chromatography column was equilibrated with ultrapure water (passed through a 0.22 μm filter). Ultrapure water was used as the eluent, and a constant flow pump was used to control the outlet flow rate at about 0.8 mL / min. The sample was dissolved in ultrapure water, the sample injection concentration was adjusted to 30 mg / mL, and the sample was filtered through a 0.22 μm microporous filter. The sample was injected, and the injection amount was 2 mL. Every 3 min, one tube of effluent was collected, and the absorbance value of the collected sample was measured at 280 nm. According to the measured results, the starting tube of the peak was determined to collect the components. Finally, four components, OS1a, OS1b, OS1c and OS1d, were obtained. Each component was concentrated by rotary evaporation at 45°C and freeze-dried. The main component of OS1a was a large molecular weight protein, and the main components of OS1b, OS1c and OS1d were small molecular weight peptides.

[0048] The OS1b component was detected to have significant concentration-dependent proliferative activity on TM3 cells. The OS1b component was subjected to HPLC-MS / MS detection, and computer analysis means was used for screening and ranking, and dozens of polypeptides with enhanced TM3 cell proliferation activity were screened, and finally the polypeptide G6-33 with the optimal TM3 cell proliferation activity was selected, and the amino acid sequence thereof is shown as SEQ ID NO: 1.

[0049] Example 2. Enzyme-linked immunosorbent assay (ELISA) for detecting testosterone content

[0050] After TM3 cells were intervened by G6-33 polypeptide at different concentrations (50, 75, and 100 μg / mL) for 24 h, the cell culture supernatant was collected, centrifuged at 3000 r / min for 20 min, and the supernatant was taken, and the testosterone content in the cell culture supernatant was detected using a testosterone ELISA kit (purchased from Shanghai Langdun Biotechnology Co., Ltd.). Specifically, the absorbance value at 450 nm of the cell culture supernatant was detected using an enzyme label instrument.

[0051] The results are shown in Table 1. Figure 1 As shown in Table 1, compared with the blank control group, the testosterone secretion content of TM3 cells under the action of G6-33 polypeptide at different concentrations (50, 75, and 100 μg / mL) was significantly increased.

[0052] Example 3. Effect of G6-33 polypeptide on mouse sexual function

[0053] Forty healthy adult male ICR mice with a body weight of 33-38 g were randomly divided into a G6-33 polypeptide low-dose group, a G6-33 polypeptide high-dose group, a positive control group, and a blank control group, 10 mice per group. The G6-33 polypeptide group was administered by gavage at a dose of 0.20 g / kg and 0.50 g / kg, and the positive control group PnTx-19 polypeptide was administered by gavage at a dose of 0.50 g / kg, and the solvent was pure water. At the same time, a pure water blank control group was set up, 1 time / day, for 30 consecutive days. Thirty female mice were given ordinary feed, and free feeding and drinking water.

[0054] The positive control group PnTx-19 polypeptide was derived from US9279004B2, and the sequence thereof is shown as SEQ ID NO: 2.

[0055] 3.1 Male mouse mating experiment method

[0056] The mating experiment was performed 60 min after the last administration. The female mice were given benzoic acid estradiol 3 days before the experiment, and were administered 10 μg per mouse subcutaneously, and were given progesterone 5 h before the experiment, and were administered 40 μg per mouse subcutaneously, so as to enter the estrus. On the night of the end of gavage, 20:00-23:00, the male mice of each group were placed in the cage in a quiet, weak light room for 5 min, and then the female mice were put in, and then the mating behavior of the mice within 20 min was observed. The sexual behavior parameters of the mice in each group were counted, including the capture latency (the time interval from putting in the female mouse to the first capture of the female mouse by the male mouse), the capture frequency (the number of times the male mouse captured the female mouse), the ejaculation latency (the time interval from putting in the female mouse to the first licking of the penis by the male mouse), and the ejaculation frequency (the number of times the male mouse licked the penis).

[0057] The results are shown in the following table. Compared with the blank control group, the capture frequency and ejaculation frequency of the mice in the G6-33 polypeptide low-dose group within 20 min were slightly increased, and the capture latency and ejaculation latency were slightly shortened; the capture frequency and ejaculation frequency of the mice in the G6-33 polypeptide high-dose group within 20 min were significantly increased, and the capture latency and ejaculation latency were significantly shortened, which was better than the blank control group and the positive control group. The speed of male sexual response and the ability of sexual activity, i.e. the degree and duration of sexual excitement, can be reflected by these indicators. The experimental results show that the oyster polypeptide G6-33 has the ability to improve sexual desire and sexual behavior, and the high dose has a more obvious promoting effect on the capture frequency and ejaculation frequency.

[0058] Table 1

[0059] Group Latency of capture / s Number of capture Latency of ejaculation / s Number of ejaculation Blank control group 57.98±11.36 9.46±1.43 310.72±68.30 4.68±0.91 PnTx-19 polypeptide group 49.58±8.23 10.95±2.33 265.01±36.15 5.81±1.39 G6-33 polypeptide low-dose group 53.98±9.17 10.23±1.67 274.56±41.22 5.79±1.67 G6-33 polypeptide high-dose group 47.96 ± 6.0 * ]] 11.80 ± 1.87 * ]] 252.98 ± 34.12 * ]] 6.22 ± 1.56 * ]]

[0060] "*" indicates P<0.05

[0061] 3.2 Detection of NO and testosterone content in serum of male mice

[0062] The body weight of the animals was measured one day before sacrifice, and the animals were fasted but not watered for 16 h on the night. After anesthesia with ether the next day, blood was taken from the eyeball, centrifuged at 4℃ and 3000 r / min for 15 min, and the serum was separated. The NO content in the serum was determined according to the operation manual of the NO detection kit (Nanjing Jiancheng Biological Engineering Institute). The testosterone content in the serum was determined by using an enzyme-linked immunoassay kit (Shanghai Langdun Biological Technology Co., Ltd.).

[0063] The results are shown in Figures 2-3 Compared with the blank control group, the testosterone ( Figure 2 ) and NO ( Figure 3 ) contents in the serum of the mice in the G6-33 polypeptide group were significantly increased in a dose-dependent manner. It is indicated that the oyster polypeptide G6-33 can strengthen the erectile ability of the penis by increasing the NO and testosterone contents of the mice.

[0064] 3.3 Organ index determination

[0065] After blood sampling, the animals were sacrificed and the testis, epididymis, seminal vesicle and prostate were accurately weighed on an electronic balance. The organ index was calculated. Organ index = organ weight / body weight x 100%.

[0066] The results are shown in Table 2. Compared with the blank control group, the testis organ index of the G6-33 polypeptide group increased slightly, and the organ indexes of other organs were basically unchanged. Figure 4 Table 2: Organ index of rats in each group

Claims

1. A Crassostrea gigas polypeptide, characterized in that, The oyster polypeptide amino acid sequence is shown as SEQ ID NO:

1.

2. A nucleic acid molecule encoding the oyster polypeptide of claim 1.

3. A vector comprising the nucleic acid molecule of claim 2.

4. An isolated host cell comprising the oyster polypeptide of claim 1, the nucleic acid molecule of claim 2, or the vector of claim 3.

5. Use of the oyster polypeptide of claim 1 for the preparation of a medicament for treating male erectile dysfunction.

6. A pharmaceutical composition comprising an effective amount of the oyster polypeptide of claim 1.

7. The pharmaceutical composition of claim 6, which is administered in the form of a lyophilized powder.

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