Abstract: By the method of artificial water contamination, and using transmission electron microscope (TEM) and flow cytometer (FCM), this paper studied the effects of cadmium on the germ cell apoptosis in testis and the quality of mature spermatozoa in epididymis of mice. Compared with that in control group, the amount of the germ cells under apoptosis in experimental groups was remarkably higher, and the ultrastructure of the germ cells showed the phenomena such as mitochondrion vacuole, karyotheca invagination, chromatin margination, and karyopyknosis, indicating that cadmium could easily cause testis spermatocyte apoptosis of mice. The proportion of the germ cells with early apoptosis was significantly higher in experimental groups than in control group, while that of active germ cells was in reverse (P<0.05). In high dosage group (0.10 mmol CdCl₂·L^-1), the survival rate of germ cells (75.1%) was significantly lower than that in control group and other experimental groups, and the early apoptosis rate of the germ cells (22.6%) was significantly higher than that of the control. The DNA breakage rates of the germ cells in testis and epididymis were significantly higher in high dosage group (18.2% and 26.5%) than in control group (3.3% and 5.6%) (P<0.05), and the amounts of testis germ cells with DNA breakage in experimental groups were lower than those of the epididymis germ cells with DNA breakage. The apoptosis rates of the germ cells in testis and epididymis increased gradually with the increase of cadmium dosage. It was concluded that the dosage of cadmium had definite effects on the apoptosis and DNA damage of mice germ cells.

Key words: cadmium, testis, germ cell, apoptosis, mature spermatozoa, paddy soil, fertilization, bacteria, archaea, diversity.