Antioxidant Enzymes Expression of the Impaired Contralateral Testes in Unilaterally Cryptorchid Rats

Objective: In this study, explored the pathologic mechanism of the contralateral testes impairment in unilaterally cryptorchid rats by investigating the gene expression level. Methods: Thirty male Sprague-Dawley rats were randomly and evenly divided into two groups: cryptorchid group and control group. Cryptorchidism was induced by surgical relocation. RT-PCR was then applied to examine the mRNA expression level of antioxidant enzymes in descended testes, including glutathione peroxidase (GSH-PX), copper/zinc-superoxide dismutase (Cu/Zn-SOD), and catalase (CAT). The concentration of malondialdehyde (MDA) was determined by spectrophotometty. In addition, germ-cell apoptosis was detected by a terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Results: Two weeks after the operation, the mRNA expression levels of GSIT-PX and Cu/Zn-SOD in the cryptorchid group were significantly downregulatted, the expression of MDA, as well as the number of apoptotic germ cells, significantly increased compared to the control group (p < 0.01). The mRNA expression of CAT did not show significant changes (p > 0.05). Conclusion: GSH-PX and SOD were downregulated in the testis contralateral to the undescended testis, leading to the accumulation of reactive oxygen species and germ-cell apoptosis. Our results may provide molecular explanations for the impairment of the descended testis in unilateral cryptorchidism.