Cadmium Induces Mouse Spermatocyte GC-2 Spd Apoptosis By Inducing Mitochondrial Damage

Objective:Cadmium is a heavy metal element with strong bioaccumulation and long-lasting toxicity.It is easy to cause damage to the male reproductive system,resulting in sperm deformity and infertility.In this study,cadmium chloride is used as the test substance to explore the effects and regulatory mechanisms of cadmium chloride（CdCl₂）on the apoptosis and mitochondrial damage of mouse spermatogenic cells（GC-2 spd cell line）.Method:GC-2 spd cells were treated with different concentrations of CdCl₂（0,2.5,5,10,20,30 and 40μM）and the cell viability was estimated based on CCK-8 data.The apoptosis of GC-2 spd cells were analyzed by flow cytometry after exposed to CdCl₂ for 24 hours.Mito Tracker Red CMXRos staining method was used to detect the morphology of mitochondria,and flow cytometry combined with JC-1 fluorescent probe was used to detect changes in mitochondrial membrane potential.The mitochondrial protein and total cellular protein of GC-2 spd cells were extracted respectively.Western blot was performed to analyze the expression of mitochondrial homeostasis-regulatory proteins Fis1 and Opa1,and the apoptosis-related proteins Bax,Bcl-2,Cytochrome C and Caspase-3 after treatment with CdCl₂ for 24 hours.Results:With increasing concentrations of CdCl₂,the survival rate of GC-2 spd cells gradually decreased,and the apoptosis rate gradually increased（P<0.05）.In the CdCl₂group（5,10μM）,the mitochondrial membrane potential decreased and mitochondrial morphology from an extended network to fragmented structures.The proportion of cells containing fragmented mitochondria gradually increased.The expression of mitochondrial fission protein Fis1 increased and the fusion protein The expression of Opa1 decreased as compared to the control group（P<0.05）.Cadmium exposure caused increases in the expression of Cytochrome C in the cytoplasm and a decreased level in the mitochondria（P<0.01）.In addition,cadmium exposure and Cleaved Caspase-3（P<0.05）.Conclusion:CdCl₂ has a toxic effect on GC-2 spd cells.It can affect the cellular distribution of Cytochrome C by regulating the homeostasis of mitochondria in cells,thereby inducing Caspase-3 mediated apoptosis.