The Effect Of Fenvalerate On Rreproductive System Of Male Rats At Puberty And The Mechanisms

Objective:Male semen quality has decreased significantly in recent years,which is related to the extensive exposure of exogenous chemicals in the environment.Pyrethroids?PYRs?pesticides with high efficiency,broad spectrum and low toxicity to mammals,are widely used in the prevention of pests in agriculture,forestry and family.Studies have shown that PYRs can lead to widespread population exposure through diet or indoor dust and have adverse effects on the male reproductive system,but the mechanism of its reproductive toxicity is not yet clear.In this study,fenvalerate?Fen?,commonly used in China,was used as the test substance,and male rats were treated by gavage during the sensitive puberty of spermatogenesis.This study aimed at analyzing the effects of fenvalerate exposure during puberty on male reproductive system and exploring its possible mechanisms.Methods:A total of 50 four-week old male SD rats were randomly divided into five groups?10 rats per group?:control group?corn oil?,low dose group?0.02 mg/kg Fen?,middle dose group?1 mg/kg Fen?,high dose group?50 mg/kg Fen?and intervention group?50 mg/kg Fen+100 mg/kg N-Acetyl-L-Cysteine?.Rats exposed to pesticides by gavage for 60 continuous days.During the exposure period,body weight,body length and anogenital distance were measured every week.24 hours after the last exposure,and the testes,liver,kidney and spleen were collected to calculate the organ coefficients.The levels of testosterone?T?,estradiol?E₂?,follicle-stimulating hormone?FSH?and luteinizing hormone?LH?in rat serum were detected by radioimmunoassay.The testicular tissue histopathology was estimated under light microscope based on HE staining,and the activity of acid phosphatase?ACP?,alkaline phosphatase?AKP?,?-glutamyl transferase??-GT?,and lactate dehydrogenase?LDH?in testes were determined using colorimetry.The semen quality was analyzed with a computer assisted semen analyzer.The activity of glutathione peroxidase?GSH-Px?,superoxide dismutase?SOD?and the content of malondialdehyde?MDA?in testes were determined using colorimetry.The apoptosis of germ cells in testes was detected using TUNEL assay and the expressions of caspase3,caspase8,Fas,Bax and Bcl-2 were measured by western blot.Results:The body weight,body length,anogenital distance and the organ coefficients of testes and liver in male rats exposed to fenvalerate were decreased in high dose group comparing with the control group?P<0.05?.The level of serum T in rats exposed to high dose group decreased significantly comparing with the control group?P<0.05?.Under the light microscope,abnormal changes of the testicular structure of rats were observed in the exposed groups,and the inner diameter of seminiferous tubules in rats increased in high dose group when compared to the control group?P<0.05?.The activities of ACP and?-GT in rat testes were decreased in low,middle and high dose groups when compared to the control group?P<0.05?.The sperm concentration and motility of rats were reduced in high dose group when compared to the control group?P<0.05?.The activities of SOD and GSH-Px in rat testes were decreased in high dose group when compared to the control group,and the content of MDA was increased?P<0.05?.Meanwhile,the cell apoptosis of testes was obviously found and the expression of pro-caspase3,active-caspase3 and pro-caspase8 was significantly up-regulated in high dose group when compared to the control group?P<0.05?.Comparing with the high dose exposure group,the testicular enzyme activity and semen quality in the intervention group increased,and oxidative stress level decreased?P<0.05?.Conclusion:Fenvalerate exposure during male rats'puberty can reduce testicular function and semen quality,which may be related with oxidative damage of testicular tissue and excessive apoptosis of germ cells.