Abstract:

Objective To investigate the protective effects of melatonin (MT) on acrylamide (AA)-induced DNA damage in rat testicular cells. Methods Forty male SD rats aged 8 weeks were randomly divided into blank control group, MT group, AA group and MT+AA group, with 10 rats in each group. MT was intraperitoneally injected at the dose of 10 mg·kg^-1·d^-1, AA was orally administrated at the dose of 25 mg·kg^-1·d^-1, and the treatment lasted for 30 d. Comet assay and Comet Assay Software Project were  employed to examine the DNA damage (comet tail length, tail DNA%, tail moment and Olive tail moment) of testicular cells, TUNEL was used to detect the cell apoptosis, the levels of 8-hydrxydeoxyguanosine (8-OHdG) in testis tissues were measured by ELISA, the levels of malondialdehyde (MDA) were measured by thiobarbituric acid method, and the activity of superoxide dismutase (SOD) was determined by xanthine oxidase method. Results Compared with blank control group, the comet tail length, tail DNA%, tail moment and Olive tail moment in testicular cells significantly increased, the number of apoptotic cells significantly increased, the levels of 8-OHdG and MDA in testis tissues significantly increased, and the activity of SOD significantly decreased in AA group (P<0.05). Compared with AA group, the DNA damage of testicular cells significantly decreased, the number of apoptotic cells significantly decreased, the levels of 8-OHdG and MDA in testis tissues significantly decreased, and the activity of SOD significantly increased in MT+AA group (P<0.05). Conclusion AA could induce DNA damage and apoptosis in rat testicular cells, and cause oxidative damage in testis. However, MT could prevent the alterations caused by AA. Oxidative damage is probably one of the mechanisms of AA-induced DNA damage in rat testicular cells.

Key words: acrylamide, melatonin, DNA damage, apoptosis, oxidative damage