弓形虫对小鼠睾丸各级生精细胞凋亡的影响

Effect of Toxoplasma Infection on the Apoptosis of Sperm in Mice

目的探讨弓形虫感染后对小鼠睾丸各级生精细胞(单倍体、二倍体、四倍体)凋亡的影响程度,进一步阐明弓形虫致雄性不育的机制。方法选用9～10周龄雄性BALB/c小鼠60只,随机分为正常对照组、弓形虫感染组(2.5×103、5×103、1×104、2×104)及阳性对照组(环磷酰胺)。采用腹腔注射法,建立弓形虫感染致小鼠睾丸损伤的模型,病理切片观察和流式细胞术检测各组小鼠睾丸各级生精细胞的凋亡情况,以及生精细胞单倍体、二倍体、四倍体三个细胞群的比例变化。结果正常对照组未出现明显的凋亡峰,处理组的单倍体、二倍体均出现明显的细胞凋亡,尤以二倍体明显,同时四倍体细胞明显减少。结论弓形虫可致睾丸各级生精细胞凋亡,对二倍体细胞的影响尤为明显;四倍体细胞显著减少。推测二倍体、四倍体细胞的凋亡及发育受阻是导致雄性生殖障碍的主要原因,导致睾丸生精细胞的损伤、精子形成障碍、少精、无精,最终导致雄性不育。

Objective To examine the effect of toxoplasma infection on the apoptosis of sperms at different stage of development, and to study the underlying mechanism of infertility. Methods Sixty BALB/c mice （9-10 weeks） were randomly divided into six groups： Control group, experimental groups （intraperitoneally injected with 2.5×10^3,5×10^3, 1×10^4 and 2×10^4 parasites）, and cyclophosphamide-treated positive control group. The number of apoptotic cells was measured by flow cytometry. Results Marked apoptosis was not observed in the cells obtained from the control group. Apoptosis was observed in diploid cells of the infected mice. Conclusion Toxoplasma infection can induce apopotosis of sperm cells, especially the diploid cells; the number of tetraploid cells were also decreased. The results suggested that infection-lnduced apoptosis of sperm cells may be the major cause of infertility.