关键词: 生殖细胞, 氧化损伤, 细胞凋亡, Caspase-9, 细胞色素C

Abstract: Abstract:Objective To study the effects of methyl mercury(MeHg) on oxidative damage, changes of cell cycle, apoptosis, and apoptosis-related protein expression in male mouse germ cells. Methods The cytotoxicity of MeHg on germ cells of male mice was measured by MTT assay. The content of malondiadehyde (MDA) and hydrogen peroxide (H₂O₂) and the activitiy of glutathione peroxidase(GSH-Px) in testicle germ cells were detected by TBA and KI colorimetric method and OPA fluorescence method. Apoptotic rate was measured by flow cytometry (FCM) and acridine orange/ethidium bromide(AO/EB) double fluorescent staining. The change of cell cycle was measured by FCM.Apoptosis-related protein expressions of Caspase-9 and CytC were detected by immunohistochemical method. Results When the cells were exposed to 0.1,1.0,10.0 and 100.0 μmol•L^-1 MeHg for 2, 4, 8, 24 and 48 h in vitro,the survival rates were decreased with the increasing of the dose of MeHg.The survival rates in groups of 1.0, 10.0, 100.0 μmol•L^-1 MeHg had significant difference compared with control group (P<0.05).After treatment with MeHg at the dose of 1/100 LD₅₀, 1/50 LD₅₀, 1/10 LD₅₀ to the mice, the results showed that with the increasing of MeHg, the contents of MDA and H₂O₂ in testis were increased.The contents of MDA in all the groups treated with MeHg were increased significantly compard with control group (P<0.05).The contents of H₂O₂ in 1/50 LD₅₀ and 1/10 LD₅₀ groups treated with MeHg were increased significantly compared with control group (P<0.01); with the increasing of MeHg,the activity of was GSH-Px decreased(P<0.05). The apoptotic rates in treated groups at the dose of 1/10 LD₅₀ were significantly higher than that in control group (P<0.05). The percentage of cells at G₂/M phase was increased with the increasing of MeHg, and the 1/50 LD₅₀ group had significant difference compared with control group (P<0.05).The expressions of Cyt C were increased in treated groups, and had significant difference compared with control group (P<0.01).The expressions of Caspase-9 were increased in treated groups, the groups of 1/50 and 1/10 LD₅₀ had significant differences compared with control group (P<0.01). Conclusion MeHg can induce cell oxidative damage, changes of cell cycle, apoptosis and changes of apoptosis-related protein expression in male mouse cells.MeHg has cytotoxic effect on male mouse germ cells.

Key words: germ cell, oxidative damage, apoptosis, Caspase-9, CytC