| Research background and objective:Azoospermia is a many causes of morbidity,the complexity of its mechanisms, and animal experiment is commonly used for its therapy research.However, with the stem cell transplantation research growing more and more extensive in recent years,to establish appropriate animal models of Azoospermia will create favorable conditions for men's infertile study.Feeding adenine,experimental varicocele, cyclophosphamide feed or intraperitoneal injection are commonly used for animal model currently,but most of their credibility is questionable because of the short follow-up time(in fact less than a spermatogenic cycle in experimental animals) and the stability of this platform for the male sterility treatment experiments.In addition, the invasive operation and cone urrent damage to the body of other systems of experimental animals lead to higher mortality rates and increase the cost of a limited experimental fund.Gonad organization is more sensitive to radiation,particularly in spermatogonia and spermatocytes of the division phase.As used for the clinical cancer radiotherapy,60Co-γcan be directly caused spermatogenic function of gonadal damage and even loss for its side effect.At the same time, total body irradiation by 60Co-γcan also cause by the hypothalamus and pituitary damage,endocrine levels disorder in the body at last.This test uses 60Co-γirradiation on the reproductive system of male mice to achieve azoospermia, to explore its role in the appropriate dosage, method and possible mechanism for male sterility of the experimental study and to provide a suitable animal modelling method.Methods:100 Kunming mice were randomly divided into Group A(n= 10),Group B(n= 15),Group C(n= 15),Group D(n= 15),Group E(n= 15),Group F(n= 15) and Group G(n= 15), Group A processed without any intervention,Group B with the intraperitoneal injection of cyclophosphamide 75 mg/(kg·d), continuously for 5 days,and the experimental Group C～G were apiece given 60Co-γ5 Gy,6 Gy,7 Gy,8 Gy and 6 Gy,with the whole body irradiation uniformity; 7 days after the first exposure,Group G were given another 4Gy's 60Co-γas the same manner. Observation of general condition, signs and body weight change were recorded went on for 35 days after the model completed;Pregnancy tests inspected,testicular weight weighed and testis index were calculated after 3 months of observation period,also FSH, LH, T, E2levels in serum were determined by enzyme-linked immunoassay and the ratio of T/E2 were calculate; HE staining pathology of testicular is observed,also the c-kit expression on the spermatogonial cell surface by immunohistochemical SABC assay.Results:After irradiation, the mice showed mental stress, hyperactivity, do not like eating in the former 4 hours, and then become apathetic spirit, dull coat, shedding, bad cold crouching;since 3 days after irradiation,the mice began to die, about 10～12 days later,its general conditions gradually recoverd, and the number of each group stabilized.Testicular tissue damage caused by irradiation induced the testicular index fallen(P<0.05), the lower T and E2 level(P<0.05),also the irradiation brought injury on hypothalamus and pituitary which leaded the FSH and LH changes(P<0.05); the surface markers c-kit of the spermatogonia in Group A expressed in the brown ring, whereas in other groups the expression performed fragment or none.Conclusions:The stabilized azoospermia animal model can be created by 60Co-γradiating twice in 6Gy and 4Gy interval. |
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