Abstract: Objective To study the injury effects of different dosage of ionizing radiation on the testicles of mice. Methods One hundred and twenty male KM mice were randomily divided into five groups at the radiation dosage of the control(0 Gy), 2.5 Gy, 3.5 Gy, 4.5 Gy and 5.5 Gy respectively. On day 3, day 7 and day 14 after ⁶⁰Coγ exposure, the epididymis index, testicle index, comparative sperm count and sperm abnormality rate were determined. The pathological changes of the testes were observed by hematoxylin and eosin stain. Results On day 3 after exposure, the epididymis index was increased, but it was decreased subsequently. The epididymis index of 4.5 Gy and 5.5 Gy groups was presented significant differences on day 14 after exposure, compared with that of the control group and day 3 group (P<0.01or P<0.05). The testicle index in each group was decreased obviously on day 7 and 14 after exposure (P<0.01or P<0.05). As to 5.5 Gy group, the testicle index was decreased significantly compared with that on day 3 after exposure (P<0.01). The sperm abnormality rate of all groups, especially in 5.5 Gy group increased significantly on day 3, 7 and 14 after exposure (P<0.01or P<0.05). The comparative sperm count of 5.5 Gy group was decreased evidently (P<0.01) and the myoid cells and basal membrane of seminiferous tubules were appeared blurry. All the index of 2.5 Gy group had no significant difference compared with those of the control group. Conclusion The injury degree of testicles in mice is positively correlated with the radiation dosage. The 3.5 Gy and 4.5 Gy are the suitable doses for establishing the model of pathological injuries in the testicles of mice.

Key words: Mice, Testicle, Ionizing radiation, Radiation injury