Polypeptide for cartilage repair and composition and application thereof

Abstract

The invention relates to a polypeptide for cartilage repair and a composition and application thereof, and belongs to the technical field of bone injury repair. The polypeptide is polypeptide PG155. Experimental results show that the polypeptide can repair cartilage injury caused by osteoarthritis to a certain extent. The further research shows that the special exosome (PG155-Exo) generated by pretreating the bone marrow mesenchymal stem cells by the polypeptide PG155 is combined with the polypeptide PG155 for use, so that the treatment effect can be obviously enhanced, and an obvious synergistic effect is shown. Due to the synergistic effect, the cartilage repair effect is obviously superior to that of a single therapy, and a more efficient treatment scheme is provided for osteoarthritis patients.

Description

Technical Field

[0001] The present invention belongs to the technical field of bone injury repair, and particularly relates to a polypeptide for cartilage repair, its composition and application. Background Art

[0002] Osteoarthritis (OA) is a chronic degenerative disease centered on the degeneration and destruction of articular cartilage. Its pathological process is complex and diverse, involving not only cartilage degeneration, ulcer formation and loss, but also a series of secondary changes such as synovial inflammation and subchondral bone plate sclerosis. Among these pathological changes, cartilage injury has become a core issue in clinical research due to its irreversibility and treatment difficulty. Articular cartilage is a highly specialized tissue whose main function is to reduce joint friction and absorb mechanical stress. However, due to the lack of blood vessels, nerves and lymphatic systems in cartilage itself, its self-repair ability is extremely limited.

[0003] In the previous research of our company (application number: CN202410805667.2), we discovered a polypeptide PG155 (N-terminal sequence is YTYQKEGLARVLQNN), which can effectively inhibit chondrocyte ferroptosis induced by interleukin-1β (IL-1β), thus providing a new idea for the prevention and treatment of osteoarthritis. However, although the previous research has clarified the potential of polypeptide PG155 in the prevention and treatment of osteoarthritis, whether it can be used to treat osteoarthritic cartilage injury and how to better realize its application in cartilage injury repair have not been deeply explored. Summary of the Invention

[0004] The purpose of the present invention is to provide a polypeptide for cartilage repair, its composition and application, so as to expand the application scope of polypeptide PG155 in the field of osteoarthritic cartilage injury treatment, and achieve the synergistic treatment of osteoarthritic cartilage injury through exosomes obtained by special treatment.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: First, the present invention provides the use of a polypeptide PG155 in the preparation of a drug for treating osteoarthritic cartilage injury, and the N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN.

[0006] Preferably, in the drug, the effective dose of the polypeptide PG155 is 0.5-1 mg / kg each time; The solvent of the drug is physiological saline; The delivery mode of the drug is intra-articular injection into the knee joint.

[0007] Second, the present invention provides the use of a polypeptide composition in the preparation of a drug for synergistically treating osteoarthritis cartilage injury, wherein the polypeptide composition is composed of polypeptide PG155 and PG155-Exo exosomes, and the N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN; The PG155-Exo exosomes are exosomes produced by bone marrow mesenchymal stem cells pretreated with polypeptide PG155.

[0008] Preferably, in the polypeptide composition, the mass ratio of the polypeptide PG155 to the PG155-Exo exosomes is 1-4:1.

[0009] Preferably, the PG155-Exo exosomes are prepared by the following preparation method: (1) Culturing bone marrow mesenchymal stem cells in DMEM medium containing 250 μg / mL polypeptide PG155 and fetal bovine serum from which exosomes have been removed by ultracentrifugation for 24 hours; (2) Changing to serum-free DMEM medium and continuing to culture for 48 hours, and collecting the supernatant; (3) Sequentially performing low-speed centrifugation, membrane filtration, high-speed centrifugation and ultracentrifugation on the collected supernatant to precipitate and purify exosomes; (4) Resuspending with PBS and then performing ultracentrifugation again to obtain PG155-Exo exosomes.

[0010] Preferably, in the drug, the effective dose of the polypeptide composition is 1-1.5 mg / kg each time; The dosage composition of the polypeptide composition is one of 1 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.5 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.8 mg / kg polypeptide PG155 and 0.2 mg / kg PG155-Exo exosomes, or 0.6 mg / kg polypeptide PG155 and 0.4 mg / kg PG155-Exo exosomes.

[0011] Preferably, the solvent of the drug is physiological saline; the delivery mode of the drug is intra-articular injection into the knee joint.

[0012] Third, the present invention provides a polypeptide composition for synergistically treating osteoarthritis cartilage injury, wherein the polypeptide composition is composed of polypeptide PG155 and PG155-Exo exosomes; The N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN; The PG155-Exo exosomes are exosomes produced by bone marrow mesenchymal stem cells pretreated with the polypeptide PG155; In the polypeptide composition, the mass ratio of the polypeptide PG155 to the PG155-Exo exosomes is 1-4:1.

[0013] Preferably, the PG155-Exo exosomes are prepared by the following preparation method: (1) Bone marrow mesenchymal stem cells were cultured for 24 hours in DMEM medium containing 250 μg / mL peptide PG155 and fetal bovine serum that had been ultracentrifuged to remove exosomes; (2) Change to serum-free DMEM medium and continue culturing for 48 hours, then collect the supernatant; (3) The collected supernatant is subjected to low-speed centrifugation, membrane filtration, high-speed centrifugation and ultracentrifugation in sequence to precipitate and purify the exosomes; (4) Resuspend in PBS and ultracentrifuge again to obtain PG155-Exo exosomes.

[0014] Preferably, the effective dose of the polypeptide composition is 1-1.5 mg / kg each time; The dosage of the polypeptide composition is one of 1 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.5 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.8 mg / kg polypeptide PG155 and 0.2 mg / kg PG155-Exo exosomes, or 0.6 mg / kg polypeptide PG155 and 0.4 mg / kg PG155-Exo exosomes; The polypeptide composition is delivered by injection into the knee joint cavity.

[0015] The beneficial effects of the present invention are: First, the present invention clarifies for the first time the role of polypeptide PG155 in treating osteoarthritis-induced cartilage damage. This discovery provides a new drug option for the treatment of osteoarthritis.

[0016] Secondly, compared with the use of polypeptide PG155 alone, the present invention creatively combines polypeptide PG155 with PG155-Exo exosomes. The experimental results show that the combined use can significantly reduce Mankin's score, restore cartilage thickness, and show significant synergistic effects. This synergistic effect makes the cartilage repair effect significantly better than single therapy, providing a more efficient treatment plan for osteoarthritis patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1Mankin's score results of the treatment effect of polypeptide PG155 on cartilage injury in osteoarthritis rats; Figure 2 Mankin's score results of the treatment effect of exosomes combined with polypeptide PG155 on cartilage injury in osteoarthritis rats; Figure 3 Electron microscopy detection results of ordinary bone marrow mesenchymal stem cell exosomes and PG155-Exo exosomes; Figure 4 Mankin's score results of the treatment effect of PG155-Exo exosomes combined with polypeptide PG155 on cartilage injury in osteoarthritis rats; Figure 5 Treatment effect of PG155-Exo exosomes combined with polypeptide PG155 on cartilage thickness in osteoarthritis rats; Figure 6 Mankin's score results of the treatment effect of different mass ratio combined drugs on cartilage injury in osteoarthritis rats; Figure 7 Treatment effect of different mass ratio combined drugs on cartilage thickness in osteoarthritis rats. Detailed implementation manners

[0018] The present invention will be further described below in conjunction with the drawings and embodiments.

[0019] Example 1 Detect the treatment effect of polypeptide PG155 on osteoarthritic cartilage injury In this experiment, 48 Sprague-Dawley (SD) rats at 4 weeks old and weighing about 200 g were selected. All experimental animals were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. The rats were adaptively fed in the laboratory environment for 7 days to ensure their adaptation to the experimental environment and maintain a healthy state. During the adaptive feeding period, the rats were raised under standard temperature (22 ± 2 °C), humidity (50 ± 10%), and lighting conditions (12-hour light / 12-hour dark cycle), and were free to ingest standard feed and drinking water.

[0020] After the adaptive feeding ended, 36 rats were randomly selected from the 48 rats for the construction of the osteoarthritis model. Before the experiment, the selected rats were anesthetized with isoflurane or sodium pentobarbital. After the rats were completely anesthetized, they were fixed on the operating table. Subsequently, the hair at the knee joint of the rats was removed, and the knee joint area was thoroughly disinfected with 75% ethanol to reduce the risk of infection.

[0021] After disinfection, 200 μL of papain solution with a concentration of 50 g / L was slowly injected into the knee joint cavity of rats using a micro syringe. For the remaining 12 rats, the same operation was performed, with the difference that the injection was an equal amount of normal saline as the control group.

[0022] Injections were made once every 2 days. After 3 injections were completed, the morphological and functional changes of the rats' knee joints were closely observed. When the rats' knee joints showed obvious swelling, limited movement, and significant abnormalities in flexion and extension functions, it indicated that the osteoarthritis model was successfully constructed.

[0023] After successful construction, in treatment group 1, 0.5 mg / kg of polypeptide PG155 solution (for 200 g rats, 100 μL of 1 mg / mL polypeptide solution was injected) was injected into the knee joint cavity; In treatment group 2, 1 mg / kg of polypeptide PG155 solution was injected into the knee joint cavity; In the control group and the model group, an equal amount of normal saline was injected into the knee joint cavity; Each group was administered drugs at a frequency of once every 7 days, for a total of 3 injections (i.e., on day 0, day 7, and day 14).

[0024] On day 21, all experimental rats were sacrificed, and the knee joint cartilage tissues were quickly removed. Subsequently, the cartilage tissues were fixed (with 4% paraformaldehyde), dehydrated, embedded (paraffin embedding), and sectioned. After the sections were stained (hematoxylin-eosin staining and safranin O staining), they were used for subsequent pathological analysis.

[0025] The Mankin's scoring method was used to evaluate the pathological damage of the rats' knee joint cartilage tissues. The scoring criteria included a total of 4 items: tidemark integrity 0 - 1 point, matrix staining 0 - 4 points, chondrocytes 0 - 3 points, and cartilage structure 0 - 6 points. The results obtained are shown in Table 1 and Figure 1 as follows.

[0026] Table 1 Therapeutic effect of polypeptide PG155 on osteoarthritic cartilage damage

[0027] From the results in Table 1, it can be seen that compared with the control group, the Mankin's score of the OA group increased significantly, indicating that the osteoarthritis cartilage damage model constructed in the present invention was successfully constructed.

[0028] Compared with the OA group, the Mankin's scores of treatment group 1 (injected with 0.5 mg / kg polypeptide PG155) and treatment group 2 (injected with 1 mg / kg polypeptide PG155) both decreased to a certain extent, indicating that polypeptide PG155 has a certain repair effect on osteoarthritic cartilage injury. However, judging from the specific numerical values of the scores, this therapeutic effect is relatively limited and fails to very significantly reverse the pathological damage state of cartilage tissue.

[0029] Example 2 Therapeutic effect of exosomes combined with polypeptide PG155 on osteoarthritic cartilage injury Existing literature shows that exosomes derived from stem cells can be used to treat osteoarthritic cartilage injury. Therefore, in this example, an attempt was made to combine stem cell exosomes with polypeptide PG155 to improve the problem of poor efficacy of PG155 used alone.

[0030] (1) Exosome acquisition Cultivate bone marrow mesenchymal stem cells (BMSCs) in DMEM containing 10% fetal bovine serum (exosomes removed by ultracentrifugation) for 24 h; Replace with serum-free DMEM medium and continue to culture for 48 h, and centrifuge to collect supernatant a; After low-speed centrifugation (centrifuge at 300 g for 10 minutes) to remove dead cells and large particles (centrifuge at 2000 g for 20 minutes), use a 0.22 μm filter membrane to filter out impurities to obtain supernatant b; Centrifuge supernatant b at 10000 g for 30 minutes, and collect supernatant c; Centrifuge supernatant c at 100000 g for 70 minutes to precipitate exosomes; Resuspend the exosomes with PBS and then centrifuge at 100000 g for 70 minutes again to obtain exosomes; Resuspend with normal saline, determine the exosome concentration by BCA method, and store at -80 °C for later use.

[0031] The electron microscopy detection results of exosomes are as Figure 3 shown in a.

[0032] (2) Therapeutic effect of exosomes combined with polypeptide PG155 on osteoarthritic cartilage injury The modeling process is the same as that in Example 1. Each group contains 12 rats, and the rats in each group are allocated according to the principle of random grouping. The experimental grouping treatments are as follows: The combined group was injected into the knee joint cavity with a mixed solution of 1 mg / kg PG155 polypeptide and 0.5 mg / kg exosomes (100 μL, the concentration of PG155 polypeptide in the mixed solution is 2 mg / mL; the concentration of exosomes is 1 mg / mL); The polypeptide group was injected with 1 mg / kg of PG155 polypeptide solution into the knee joint cavity; The exosome group was injected with 0.5 mg / kg of exosome solution into the knee joint cavity; The control group was injected with an equal volume of normal saline.

[0033] Each group of animals was administered drugs at a frequency of once every 7 days for a total of 3 injections (i.e., on day 0, day 7, and day 14).

[0034] On day 21, all experimental rats were sacrificed, and the knee joint cartilage tissues were quickly removed. After the cartilage tissues were successively fixed (4% paraformaldehyde), dehydrated, embedded (paraffin embedding), sectioned, and stained (hematoxylin-eosin staining and safranin O staining), the pathological damage of the rat knee joint cartilage tissues was evaluated using the Mankin's scoring method, and the results obtained are shown in Table 2 and Figure 2.

[0035] Table 2 Therapeutic effect of exosomes combined with polypeptide PG155 on osteoarthritic cartilage injury

[0036] From the results in Table 2, it can be seen that the Mankin's score of the OA group was significantly higher than that of the control group, indicating that the modeling was successful.

[0037] The Mankin's scores of the polypeptide group, exosome group, and combined group were all significantly lower than that of the OA group, indicating that the three treatment methods all had a certain therapeutic effect on osteoarthritic cartilage injury. Moreover, the effect of the combined group was significantly better than that of the polypeptide group and the exosome group.

[0038] To further detect the effect of the combination, a synergy analysis of the composition was carried out in this example: According to the Jin Zhengjun formula q = E(a + b) / (Ea + Eb - Ea×Eb), it was evaluated whether there was a synergistic effect between the combination of PG155 polypeptide and bone marrow mesenchymal stem cell exosomes in the combined group. In the formula, E(a + b) is the therapeutic effect of the combined group, Ea is the therapeutic effect of the polypeptide group, and Eb is the therapeutic effect of the exosome group.

[0039] Among them, compared with the OA group, the therapeutic effect of the polypeptide group was 26.72% ((OA group - polypeptide group) / OA group), the therapeutic effect of the exosome group was 31.71%, and the therapeutic effect of the combined group was 55.46%.

[0040] According to the Jin Zhengjun formula, the calculated q value was 1.11, slightly lower than the threshold of the synergistic effect, indicating that the combination of polypeptide PG155 and exosomes showed an additive effect rather than a significant synergistic effect in the treatment of osteoarthritic cartilage injury.

[0041] Example 3 The results of Example 2 showed that the combination of ordinary exosomes and polypeptide PG155 only presented an additive effect and no obvious synergistic effect. Therefore, in this example, BMSCs were pretreated with PG155 to produce specially treated exosomes (PG155-Exo), and the synergistic therapeutic effect of their combination with polypeptide PG155 on osteoarthritic cartilage injury was explored.

[0042] (1) Obtaining of PG155-Exo exosomes Bone marrow mesenchymal stem cells (BMSCs) were cultured in DMEM containing 250 μg / mL polypeptide PG155 and 10% fetal bovine serum (exosomes removed by ultracentrifugation) for 24 h; It was replaced with serum-free DMEM medium and continued to be cultured for 48 h, and the supernatant a was collected by centrifugation; After removing dead cells and large particles by low-speed centrifugation, impurities were removed by filtration through a 0.22 μm filter membrane to obtain supernatant b; The supernatant b was centrifuged at 10,000 g for 30 minutes, and the supernatant c was collected; The supernatant c was ultracentrifuged at 100,000 g for 70 minutes to precipitate exosomes; After the exosomes were resuspended with PBS, they were ultracentrifuged at 100,000 g for 70 minutes again to obtain PG155-Exo exosomes; After resuspending with normal saline, the concentration of PG155-Exo exosomes was measured by BCA method and stored at -80 °C for later use.

[0043] The electron microscopy detection results of exosomes are as Figure 3 shown in b. Compared with the exosomes of untreated bone marrow mesenchymal stem cells, the volume of the exosomes obtained after PG155 treatment was significantly increased, so it may contain more contents.

[0044] (2) Therapeutic effect of the combination of exosomes and polypeptide PG155 on osteoarthritic cartilage injury The modeling process was the same as that in Example 1. Each group contained 12 rats, and the rats in each group were allocated according to the principle of random grouping. The experimental grouping treatments were as follows: In the combined group, 1 mg / kg PG155 polypeptide and 0.5 mg / kg PG155-Exo exosomes were injected into the knee joint cavity; In the polypeptide group, 1 mg / kg PG155 polypeptide was injected into the knee joint cavity; In the exosome group, 0.5 mg / kg PG155-Exo exosomes were injected into the knee joint cavity; In the control group and the OA group, an equal amount of normal saline was injected into the knee joint cavity.

[0045] Each group of animals was administered the drug at a frequency of once every 7 days for a total of 3 injections (i.e., on day 0, day 7, and day 14).

[0046] On day 21, all experimental rats were sacrificed, and the knee joint cartilage tissue was quickly removed. After the cartilage tissue was successively fixed (4% paraformaldehyde), dehydrated, embedded (paraffin embedding), sectioned, and stained (hematoxylin-eosin staining and safranin O staining), the Mankin's scoring method was used to evaluate the pathological damage of the rat knee joint cartilage tissue, and the results are shown in Table 3 and Figure 4 as follows.

[0047] Table 3 Therapeutic effect of the combination of PG155-Exo exosomes and polypeptide PG155 on osteoarthritic cartilage injury

[0048] As can be seen from the results of Table 3 and Figure 4, the Mankin's score of the combined group was significantly lower than that of the polypeptide group and the PG155-Exo exosome group, and compared with the results in Table 2, the Mankin's score of the combined group was significantly lower than that of the group treated with the combination of ordinary exosomes and PG155.

[0049] Compared with the OA group, the therapeutic effect of the polypeptide group was 25.71%, the therapeutic effect of the PG155-Exo exosome group was 44.80%, and the therapeutic effect of the combined group was 80.00%.

[0050] According to the Jin Zhengjun formula q = E(a + b) / (Ea + Eb - Ea×Eb), it was evaluated whether there was a synergistic effect in the combination of PG155 polypeptide and PG155-Exo exosomes in the combined group. In the formula, E(a + b) is the therapeutic effect of the combined group, Ea is the therapeutic effect of the polypeptide group, and Eb is the therapeutic effect of the PG155-Exo exosome group.

[0051] The calculated q value was 1.36, which was greater than 1.15, indicating that the combination of PG155-Exo exosomes produced by pretreatment with polypeptide PG155 and polypeptide PG155 had a significant synergistic effect in the treatment of osteoarthritic cartilage injury.

[0052] To further verify the therapeutic effect of the combination of polypeptide PG155 and PG155-Exo exosomes, the cartilage thickness from the cartilage surface to the tidemark was calculated using the ImageJ analysis software, and the results are shown in Table 4 and Figure 5 as follows.

[0053] Table 4 Therapeutic effect of the combination of PG155-Exo exosomes and polypeptide PG155 on the cartilage thickness of osteoarthritis

[0054] As can be seen from Table 4 and Figure 5, similar to the Mankin's scoring results, the cartilage thickness in the OA group decreased significantly, while compared with the OA group, the cartilage thickness in the polypeptide group, PG155-Exo exosome group, and combination group all increased significantly.

[0055] Compared with the OA group, the treatment effect of the polypeptide group was 25.25%, that of the PG155-Exo exosome group was 42.07%, and that of the combination group was 85.14%.

[0056] According to the Jin Zhengjun formula q = E(a + b) / (Ea + Eb - Ea×Eb), evaluate whether there is a synergistic effect in the combined use of PG155 polypeptide and PG155-Exo exosomes in the combination group. In the formula, E(a + b) is the treatment effect of the combination group, Ea is the treatment effect of the polypeptide group, and Eb is the treatment effect of the PG155-Exo exosome group.

[0057] The q value calculated by the Jin Zhengjun formula was 1.50, which was greater than 1.15, indicating that the PG155-Exo exosomes produced after pretreatment with polypeptide PG155 and polypeptide PG155 could synergistically increase the cartilage thickness when used in combination, further verifying the synergistic effect of the two on cartilage damage in osteoarthritis.

[0058] Example 4 To detect whether the combined use of polypeptide PG155 and PG155-Exo exosomes with different mass ratios has the same synergistic effect, in this example, while controlling the total dosage of the drug at 1 mg unchanged, the treatment effects of combined drugs with different mass ratio combinations were detected.

[0059] The modeling process was the same as in Example 1 (6 rats in each group, meeting random grouping), and the grouping was as follows: The control group and the OA group were injected with an equal amount of normal saline into the knee joint cavity; The polypeptide group was injected with 1 mg / kg of PG155 polypeptide into the knee joint cavity; The exosome group was injected with 1 mg / kg of PG155-Exo exosomes into the knee joint cavity; Combination group a was injected with 0.5 mg / kg of PG155 polypeptide and 0.5 mg / kg of PG155-Exo exosomes into the knee joint cavity; Combination group b was injected with 0.8 mg / kg of PG155 polypeptide and 0.2 mg / kg of PG155-Exo exosomes into the knee joint cavity; Combination group b was injected with 0.6 mg / kg of PG155 polypeptide and 0.4 mg / kg of PG155-Exo exosomes into the knee joint cavity; Each group of animals was administered the drug at a frequency of once every 7 days for a total of 3 injections (i.e., on day 0, day 7, and day 14).

[0060] On day 21, all experimental rats were sacrificed, and the knee joint cartilage tissues were quickly removed. After the cartilage tissues were successively fixed (4% paraformaldehyde), dehydrated, embedded (paraffin embedding), sectioned, and stained (hematoxylin-eosin staining and safranin O staining), the pathological damage of the rat knee joint cartilage tissues was evaluated using the Mankin's scoring method, and the results are shown in Table 5 and Figure 6 and Figure 7 as shown.

[0061] Table 5 Therapeutic effect of the combination of PG155-Exo exosomes and polypeptide PG155 on osteoarthritic cartilage injury

[0062] It can be clearly observed from the results in Table 5 and Figure 6 and Figure 7 that compared with the "polypeptide group" using only PG155 polypeptide or the "PG155-Exo exosome group" using only PG155-Exo exosomes, the three combined groups (combined group a, combined group b, and combined group c) showed a significant decrease in Mankin's score, while the cartilage thickness increased significantly. This indicates that when the total drug dosage remains unchanged, the combination of PG155 polypeptide and PG155-Exo exosomes can produce a synergistic effect, thus more effectively improving cartilage damage related to osteoarthritis.

[0063] Further analysis showed that there were certain differences in the therapeutic effects of different mass ratio combination drug regimens. Specifically, combined group a used a mass ratio of 1:1, combined group b used a mass ratio of 4:1, and combined group c used a mass ratio of 3:2 for compatibility. It was found that although all three ratios showed a certain synergistic effect, when PG155 polypeptide and PG155-Exo exosomes were combined at a mass ratio of 1:1, the therapeutic effect was the most significant. This ratio not only reduced the Mankin's score to the lowest level but also maximally restored the cartilage thickness, showing the best cartilage repair ability.

Claims

1. Use of a polypeptide PG155 in the preparation of a drug for treating cartilage injury of osteoarthritis, characterized in that, The N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN.

2. The use according to claim 1, wherein In the said drug, the effective dose of the polypeptide PG155 is 0.5 - 1 mg / kg per time; The solvent of the said drug is physiological saline; The delivery method of the said drug is intra-articular injection into the knee joint.

3. Use of a polypeptide composition in the preparation of a drug for the synergistic treatment of osteoarthritis cartilage injury, characterized in that, The said polypeptide composition consists of polypeptide PG155 and PG155-Exo exosomes, and the N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN; The said PG155-Exo exosomes are exosomes produced by bone marrow mesenchymal stem cells pretreated with polypeptide PG155.

4. The use according to claim 3, characterized in that, In the said polypeptide composition, the mass ratio of the polypeptide PG155 to the PG155-Exo exosomes is 1 - 4:

1.

5. The use according to claim 3, characterized in that, The said PG155-Exo exosomes are prepared by the following preparation method: (1) Cultivate bone marrow mesenchymal stem cells in DMEM medium containing 250 μg / mL polypeptide PG155 and fetal bovine serum from which exosomes have been removed by ultracentrifugation for 24 hours; (2) Replace it with serum-free DMEM medium and continue to culture for 48 hours, and collect the supernatant; (3) Centrifuge the collected supernatant successively at low speed, filter through a membrane, centrifuge at high speed and ultracentrifuge to precipitate and purify the exosomes; (4) Resuspend with PBS and then ultracentrifuge again to obtain PG155-Exo exosomes.

6. The use according to claim 4, characterized in that, In the said drug, the effective dose of the said polypeptide composition is 1 - 1.5 mg / kg per time; The dosage composition of the said polypeptide composition is one of 1 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.5 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.8 mg / kg polypeptide PG155 and 0.2 mg / kg PG155-Exo exosomes, or 0.6 mg / kg polypeptide PG155 and 0.4 mg / kg PG155-Exo exosomes.

7. The use according to claim 6, characterized in that, The solvent of the said drug is physiological saline; the delivery method of the said drug is intra-articular injection into the knee joint.

8. A polypeptide composition for synergistically treating cartilage injury of osteoarthritis, characterized in that, The said polypeptide composition consists of polypeptide PG155 and PG155-Exo exosomes; The N-terminal sequence of the polypeptide PG155 is YTYQKEGLARVLQNN; The said PG155-Exo exosomes are exosomes produced by bone marrow mesenchymal stem cells pretreated with polypeptide PG155; In the said polypeptide composition, the mass ratio of the polypeptide PG155 to the PG155-Exo exosomes is 1 - 4:

1.

9. The polypeptide composition according to claim 8, wherein The said PG155-Exo exosomes are prepared by the following preparation method: (1) Cultivate bone marrow mesenchymal stem cells in DMEM medium containing 250 μg / mL polypeptide PG155 and fetal bovine serum from which exosomes have been removed by ultracentrifugation for 24 hours; (2) Replace it with serum-free DMEM medium and continue to culture for 48 hours, and collect the supernatant; (3) Centrifuge the collected supernatant successively at low speed, filter through a membrane, centrifuge at high speed and ultracentrifuge to precipitate and purify the exosomes; (4) After resuspension with PBS, ultracentrifugation was performed again to obtain PG155-Exo exosomes.

10. The polypeptide composition according to claim 9, wherein The effective dose of the polypeptide composition is 1-1.5 mg / kg per time; The dosage composition of the polypeptide composition is one of 1 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.5 mg / kg polypeptide PG155 and 0.5 mg / kg PG155-Exo exosomes, 0.8 mg / kg polypeptide PG155 and 0.2 mg / kg PG155-Exo exosomes, or 0.6 mg / kg polypeptide PG155 and 0.4 mg / kg PG155-Exo exosomes; The delivery method of the polypeptide composition is intra-articular injection into the knee joint.

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