Method for assessing the damage of ionizing radiation to male sperm quality

Abstract

The application discloses a method for evaluating damage of male sperm quality caused by ionizing radiation, and belongs to the technical field of reproductive biology, and comprises the following steps: establishing a dose-effect database model between ionizing radiation dose and male sperm quality based on a logistic regression model, and determining a mapping relationship between sperm quality rating and average time for recovery of fertility; collecting a semen sample to be measured exposed to ionizing radiation, comparing the semen sample to be measured with the dose-effect database model, evaluating male sperm quality rating, and predicting time required for recovery of fertility based on the male sperm quality rating and the mapping relationship.

Description

Technical Field

[0001] This invention belongs to the field of reproductive biology technology, specifically relating to a method for assessing the damage of ionizing radiation to male sperm quality. Background Technology

[0002] With economic development and technological progress, individuals such as pilots, nuclear medicine personnel, nuclear power plant workers, nuclear physics researchers, irradiation processing workers, and cancer patients undergoing radiotherapy are inevitably exposed to ionizing radiation. The International Commission on Radiological Protection (ICRP) clearly states that the testes and spermatogenesis processes are highly sensitive to ionizing radiation. Spaceflight can lead to a significant decrease in serum, urine, and saliva testosterone concentrations in male astronauts; studies have shown that therapeutic doses greater than 6 Gy can cause permanent azoospermia in men. Furthermore, male parents exposed to ionizing radiation can pass on the biological effects of parental radiation exposure to unexposed offspring through germ cells. Exposure to ionizing radiation in male mice not only increases the mutation rate in offspring somatic cells but also increases the instability of repetitive DNA sequences in offspring germ cell lines.

[0003] Numerous animal experiments and epidemiological studies have shown that exposure to ionizing radiation leads to decreased male fertility and adverse effects on offspring health. However, there is currently a lack of methods to assess sperm quality damage following ionizing radiation exposure. Furthermore, while the male reproductive system undergoes a damage-repair process after ionizing radiation exposure, there are no reported studies predicting subsequent sperm quality damage and fertility recovery. Summary of the Invention

[0004] In view of the above, the purpose of this invention is to provide a method for assessing the damage of ionizing radiation to male sperm quality. A dose-response database model is established using male mice exposed to different doses of gamma radiation to determine the relationship between ionizing radiation dose and male sperm quality. This database model is then used to analyze semen samples exposed to ionizing radiation, assess the extent of sperm quality damage caused by ionizing radiation exposure, and predict the time required for fertility recovery. This invention has multiple advantages, including high feasibility, simple and rapid assessment, and high accuracy.

[0005] To achieve the above-mentioned objective, an embodiment provides a method for assessing the damage of ionizing radiation to male sperm quality, comprising the following steps:

[0006] A dose-response database model was established based on logistic regression to establish the relationship between ionizing radiation dose and male sperm quality, and the mapping relationship between sperm quality rating and average time to fertility recovery was determined.

[0007] Semen samples exposed to ionizing radiation were collected and compared with a dose-response database model to assess male sperm quality rating. Based on the male sperm quality rating and the mapping relationship, the time required for fertility recovery was predicted.

[0008] Preferably, a dose-effect database model is established based on a logistic regression model to establish the relationship between ionizing radiation dose and male sperm quality, including:

[0009] Different time points after acute gamma radiation t n Semen samples were collected from male mice in different radiation dose groups, and semen parameters were detected by computer-aided semen analysis.

[0010] For each time point, an ordered logistic regression model was established for the semen parameters detected at different radiation doses:

[0011]

[0012] in, Y Let be the dependent variable, representing sperm quality rating, and N be the total number of sperm quality rating levels. j For sperm quality rating index, For the first j The constant term of the regression, ~ The independent variable is denoted as , representing the total. m Semen parameters at each time point t n Down, ~ They are respectively independent variable ~ The regression coefficients, P () indicates the probability of sperm quality rating;

[0013] The above ordered logistic regression model represents the different sperm quality ratings at different time points. Each part contains a corresponding equation, thus establishing a dose-effect database model between ionizing radiation dose and male sperm quality.

[0014] Preferably, the semen parameters include sperm concentration, sperm motility, abnormal sperm rate, average path velocity, linear velocity, curvilinear velocity, lateral head displacement, oscillation crossover frequency, and linearity.

[0015] Preferably, determining the mapping relationship between sperm quality rating and the average time for fertility recovery includes:

[0016] At different time points after radiation t nMale mice in different dosage groups were housed with normal female mice. Mating was determined daily by observing the vaginal plugs of the female mice. Successful mating, pregnancy, and the birth of healthy newborn mice were inferred from the gestation period of 18-22 days. The average time for successful mating and the production of healthy newborn mice in different dosage groups was recorded. T a That is, the average duration from the first day of being put together in the cages to successful mating. T a As a measure of average fertility recovery time, a mapping relationship between different sperm quality ratings and average fertility recovery time was established.

[0017] Preferably, the method for delivering normal newborn mice includes:

[0018] A comprehensive assessment of the health of mice at different ages was conducted, including routine HE staining, glucose and lipid metabolism, reproductive function, behavior and cognition. If the assessment results showed no statistical difference compared with the offspring mice of the same age in the 0 Gy dose group, the mice were considered to have given birth to normal newborn mice.

[0019] Preferably, the semen sample to be tested is compared with a dose-response database model to assess the male sperm quality rating, including:

[0020] Based on the duration of ionizing radiation, the ordered logistic regression model with the closest time frame is selected from the dose-effect database model. The semen parameters of the semen sample to be tested are input into the selected ordered logistic regression model to calculate the probability of different sperm quality ratings. The sperm quality rating with the highest probability is determined as the male sperm quality rating of the semen sample to be tested.

[0021] Preferably, predicting the time required for fertility recovery based on male sperm quality rating and mapping relationship includes:

[0022] The average time for fertility recovery corresponding to the male sperm quality rating in the mapping relationship is determined as the time required for fertility recovery.

[0023] Preferably, the method further includes: adopting a rolling dynamic update scheme, using the semen sample to be tested as cumulative sample data, accumulating to a certain proportion, conducting admission assessment and screening, re-analyzing together with the original data, generating an iterative model, and comparing it with historical versions to select the model with higher accuracy.

[0024] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0025] (1) This method is highly targeted and can more accurately assess the damage to male sperm quality caused by ionizing radiation exposure compared to conventional sperm quality assessment methods.

[0026] (2) This method is highly feasible, simple and fast in assessment, low in cost, highly accurate, and requires simple instruments and equipment. This method is a continuous and dynamic monitoring and management method. It can not only provide an initial baseline assessment of sperm quality and a prediction of fertility recovery time after exposure to ionizing radiation, but also dynamically track changes in sperm quality damage rating during the fertility damage-recovery process.

[0027] (3) This method can predict the time for male fertility recovery after exposure to ionizing radiation, and avoid premature mating leading to embryo quality risks. This method minimizes the risk of birth defects in offspring that may be caused by paternal exposure to ionizing radiation, and will provide a systematic methodological reference for rapid assessment and dynamic adjustment in future clinical practice. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of the method for assessing the damage of ionizing radiation to male sperm quality provided in the embodiments;

[0030] Figure 2 This is a flowchart of the method for assessing the damage of ionizing radiation to male sperm quality provided in the embodiments;

[0031] Figure 3 This is a schematic diagram of the mathematical model of the dose-effect database provided in the embodiment;

[0032] Figure 4 This is a data fitting diagram illustrating the mapping relationship between sperm quality rating and average time to fertility recovery provided in the example;

[0033] Figure 5 This is a three-dimensional bar chart showing the mapping relationship between sperm quality rating and average time to fertility recovery provided in the example. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of this invention.

[0035] like Figure 1 and Figure 2 As shown in the embodiment, an assessment method for the damage of ionizing radiation to male sperm quality includes the following steps:

[0036] S1. A dose-effect database model between ionizing radiation dose and male sperm quality was established based on a logistic regression model, and the mapping relationship between sperm quality rating and average time to fertility recovery was determined.

[0037] In this embodiment, the specific process of constructing the dose-response database model includes:

[0038] (1) At different time points after acute gamma radiation t n Semen samples were collected from male mice in different radiation dose groups, and semen parameters were detected using computer-aided semen analysis.

[0039] Specifically, 700 male C57 mice aged 10 weeks were used and received different doses of [agents / resources]. 137 Acute gamma radiation of Cs. Based on preliminary experiments, it was found that when the acute gamma radiation dose was greater than 6 Gy, the mortality rate of male rats exceeded 50% within one week after radiation. Therefore, they were divided into 7 dose groups {0 Gy, 1 Gy, 2 Gy, 3 Gy, 4 Gy, 5 Gy, 6 Gy}, with 100 rats randomly assigned to each group. Based on the approximately 35-day spermatogenesis cycle in mice, five time points were selected: 0 hours, 1 week, 5 weeks, 10 weeks, and 15 weeks post-irradiation. Ten male mice in each dose group were sacrificed via inhalation anesthesia. Bilateral epididymis were removed from each male mouse, and each epididymis was placed in 600 μL of preheated M199 solution and minced with ophthalmic scissors. After incubation at 37°C for 3 minutes, a small amount of suspension was collected to prepare a sperm smear. After staining, the abnormal sperm rate was observed under a microscope. Simultaneously, another 20 μL of the suspension was placed on a slide, and sperm analysis was performed using a sperm analyzer to obtain eight semen parameters: sperm concentration, sperm motility, average path velocity, linear velocity, curvilinear velocity, lateral head displacement, swing crossing frequency, and linearity. The average of the bilateral epididymal semen parameters was taken as the semen parameters for that mouse.

[0040] (2) For each time point, an ordered logistic regression model was established for the semen parameters detected at different radiation doses.

[0041] Specifically, the ordered logistic regression model used is as follows:

[0042]

[0043] in, Y Y is the dependent variable, representing sperm quality rating, and N is the total number of sperm quality rating grades. The total number of sperm quality rating grades is the same as the total number of dose groups. When Y equals N, it corresponds to the 0 Gy dose group. j For sperm quality rating index, For the firstj The constant term of the regression, ~ The independent variable is denoted as , representing the total. m Semen parameters at each time point t n Down, ~ They are respectively independent variable ~ The regression coefficients, P () indicates the probability of sperm quality rating;

[0044] The above ordered logistic regression model represents the different sperm quality ratings at different time points. Each part contains a corresponding equation, thus establishing a dose-effect database model between ionizing radiation dose and male sperm quality.

[0045] In practice, after setting variables, the semen parameters of mice in different dose groups at different time points after radiation are input, and ordered logistic regression analysis is performed to obtain the constant term and regression coefficients, thereby establishing the corresponding model, such as... Figure 3 As shown.

[0046] In this embodiment, the mapping relationship between sperm quality rating and average fertility recovery time was also determined. Specifically, at five time points after radiation, 10 male mice from each dose group were placed in cages with normal female mice. Mating was determined daily by observing the vaginal plugs of the female mice. The gestation period of 18-22 days was used to infer whether mating was successful, whether the female mouse became pregnant, and whether she gave birth to normal newborn mice. The duration of successful mating and the production of normal newborn mice in each of the 10 male C57 mice in different dose groups at each time point was recorded (i.e., the number of days from the first day of placement to successful mating). The average duration of the 10 mice was taken as the average fertility recovery time for that dose group at that time point. A mapping relationship between sperm quality rating and average fertility recovery time was constructed and recorded in a dose-effect database, such as... Figure 4 and Figure 5 As shown.

[0047] In this embodiment, the method for producing normal newborn mice was as follows: Mice were comprehensively assessed for health on the day of birth, at 3 weeks of age, 10 weeks of age, 6 months of age, and 18 months of age. This included routine HE staining (all organs), glucose and lipid metabolism (GTT, ITT, blood lipid measurements, and expression levels of related important genes), reproductive function (sex hormone levels, follicle development at each stage, semen analysis, cage co-location test, etc.), and behavior and cognition (open field test, novel object recognition test, water maze, etc.). If the results showed no statistically significant difference compared to the offspring mice of the same age in the 0 Gy dose group, the mice were considered to have produced normal newborn mice.

[0048] S2. Collect semen samples exposed to ionizing radiation, compare the semen samples with the dose-response database model, assess the male sperm quality rating, and predict the time required for fertility recovery based on the male sperm quality rating and mapping relationship.

[0049] In this embodiment, when assessing male sperm quality rating, the ordered logistic regression model with the closest time frame is selected from the dose-response database model based on the duration after ionizing radiation. The semen parameters of the semen sample to be tested are input into the selected ordered logistic regression model to calculate the probability of different sperm quality ratings. The sperm quality rating with the highest probability is determined as the male sperm quality rating of the semen sample to be tested.

[0050] Specifically, one week after acute gamma radiation exposure, semen was collected from one of ten male mice and analyzed. The ordered logistic regression model set for one week post-radiation was retrieved from the dose-response database. Substituting the semen data into the equations, the following values ​​were obtained: P(Y≤1) = 0.04, P(Y≤2) = 0.09, P(Y≤3) = 0.14, P(Y≤4) = 0.26, P(Y≤5) = 0.74, P(Y≤6) = 0.91. These were then converted to P(Y=1) = 0.04, P(Y=2) = 0.05, P(Y=3) = 0.05, P(Y=4) = 0.12, P(Y=5) = 0.48, P(Y=6) = 0.17, and P(Y=7) = 0.09. The sperm quality grade with the highest probability was selected, and the sperm quality rating one week after radiation was grade 5 (grade 7 is normal). Three months after radiation, semen was collected again from one of the male mice, and the dynamic change in sperm quality rating was evaluated similarly, resulting in a grade 6.

[0051] In this embodiment, the time required for fertility recovery is also predicted based on the male sperm quality rating and mapping relationship, that is, the average time for fertility recovery corresponding to the male sperm quality rating in the mapping relationship is determined as the time required for fertility recovery.

[0052] Specifically, semen samples from male mice were collected on the day of acute gamma radiation exposure and analyzed. Sperm quality was assessed as grade 2 based on the dose-response database model. The time required for fertility recovery at different post-radiation time points was retrieved from the dose-response database model. It was recommended to wait 9 weeks before mating to minimize the risk of birth defects in offspring potentially caused by paternal ionizing radiation exposure. Semen quality was reassessed before mating.

[0053] In this embodiment, a rolling dynamic update scheme is adopted. Data on the duration of ionizing radiation, semen parameters, and the duration of normal offspring reproduction in male mice are used as cumulative samples. After accumulating to a certain proportion, an admission assessment and screening are conducted. The data are then re-analyzed together with the original data to generate an iterative model. The model is then compared with historical versions, and the model with higher accuracy is selected.

[0054] The method described in the examples establishes a dose-effect database model between ionizing radiation dose and male sperm quality using male mice exposed to ionizing radiation. This model assesses the damage to male sperm quality after ionizing radiation and predicts the time required for fertility recovery, thus providing a systematic approach for rapid assessment and dynamic adjustment in clinical practice.

[0055] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above description is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for assessing the damage of ionizing radiation to male sperm quality, characterized in that, Includes the following steps: A dose-response database model was established based on logistic regression to establish the relationship between ionizing radiation dose and male sperm quality, and the mapping relationship between sperm quality rating and the average time to fertility recovery was determined, including: Different time points after acute gamma radiation t n Semen samples were collected from male mice in different radiation dose groups, and semen parameters were detected by computer-aided semen analysis. For each time point, an ordered logistic regression model was established for the semen parameters detected at different radiation doses: in, Y The dependent variable is denoted by , representing sperm quality rating, and N is the total number of sperm quality rating levels. j For sperm quality rating index, For the first j The constant term of the regression, ~ The independent variable is , representing the total. m Semen parameters at each time point t n Down, ~ They are respectively independent variable ~ The regression coefficients, P () indicates the probability of sperm quality rating; The above ordered logistic regression model represents the different sperm quality ratings at different time points. Each part contains a corresponding equation, thereby establishing a dose-effect database model between ionizing radiation dose and male sperm quality; Semen samples exposed to ionizing radiation were collected, and the samples were compared with a dose-response database model to assess male sperm quality rating. This included: selecting the ordered logistic regression model with the closest time frame from the dose-response database model based on the duration of ionizing radiation exposure; inputting the semen parameters of the sample into the selected ordered logistic regression model to calculate the probability of different sperm quality ratings; and determining the sperm quality rating with the highest probability as the male sperm quality rating of the sample. Predicting the time required for fertility recovery based on male sperm quality rating and mapping relationship.

2. The method for assessing the damage to male sperm quality caused by ionizing radiation according to claim 1, characterized in that, The semen parameters include sperm concentration, sperm motility, abnormal sperm rate, average path velocity, linear velocity, curvilinear velocity, lateral head displacement, swing crossover frequency, and linearity.

3. The method for assessing the damage to male sperm quality caused by ionizing radiation according to claim 1, characterized in that, Determine the mapping relationship between sperm quality rating and the average time to fertility recovery, including: At different time points after radiation t n Male mice in different dosage groups were housed with normal female mice. Mating was determined daily by observing the vaginal plugs of the female mice. Successful mating, pregnancy, and the birth of healthy newborn mice were inferred from the gestation period of 18-22 days. The average time for successful mating and the production of healthy newborn mice in different dosage groups was recorded. T a That is, the average duration from the first day of being put together in the cages to successful mating. T a As a measure of average fertility recovery time, a mapping relationship between different sperm quality ratings and average fertility recovery time was established.

4. The method for assessing the damage to male sperm quality caused by ionizing radiation according to claim 3, characterized in that, Methods for delivering normal newborn mice include: A comprehensive assessment of the health of mice at different ages was conducted, including routine HE staining, glucose and lipid metabolism, reproductive function, behavior and cognition. If the assessment results showed no statistical difference compared with the offspring mice of the same age in the 0 Gy dose group, the mice were considered to have given birth to normal newborn mice.

5. The method for assessing the damage to male sperm quality caused by ionizing radiation according to claim 1, characterized in that, Predicting the time required for fertility recovery based on male sperm quality rating and mapping relationship, including: The average time for fertility recovery corresponding to the male sperm quality rating in the mapping relationship is determined as the time required for fertility recovery.

6. The method for assessing the damage to male sperm quality caused by ionizing radiation according to claim 1, characterized in that, Also includes: A rolling dynamic update scheme is adopted, using the semen samples to be tested as cumulative sample data. After accumulating to a certain proportion, an admission assessment and screening are carried out. The data are then re-analyzed together with the original data to generate an iterative model, which is then compared with historical versions to select the model with higher accuracy.

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