Study On The Toxicity Mechanism Of Acrylonitrile On Germ Cells In Male Mice

Objective To explore the toxicity mechanism of acrylonitrile(AN)on germ cells by observing the inducing effect of AN on the germ cell apoptosis,the influence on sperm quality and morphology during spermatogenesis in male mice,in order to provide some theoretical data for protecting the health of occupational exposure population group induced by AN.Methods According to the body weight 250 adult male mice in SPF degree were randomly divided into 5 groups,including negative control group(normal saline 0.01ml/g),AN1.25mg/kg.AN2.50mg/kg,AN5.00mg/kg and positive control group (cytoxan 40mg/kg),each group had 50 mice.The mice were exposed by daily intraperitoneal injection for five days(the injected dose was 0.01ml/g and cytoxan only for once).All mice were sacrificed in batch by cervical dislocation at the 7th, 14th,21th,28th,35th day respectively after the first administration. (1) Combining with experiments research results on mice testis exposed to AN organizational structure,the germ cell cycle and serum testosterone influence,Bcl-2 and Bax protein expression in spermatogenic cells were detected by immunohistochemical method,to discuss the mechanism of reproductive functions influence of AN on male mice. (2) Mice sperm quality (sperm density,vitality,living rate,motility and sperm movement parameters) were measured with WLJY-9000 color-detection system of sperm quality. (3) Sperm morphology were observed through Hematoxylin-Eosin staining under the microscope.Results (1) Bcl-2 and Bax protein expression in spermatogenic cells:Mean optical density of Bcl-2:They were significantly lower in AN2.50mg/kg group of all observation times and in 21d AN1.25mg/kg group(P<0.05);Mean optical density of Bax:In addition to 21 d AN1.25mg/kg group,the others were significantly higher than the negative control group (P<0.05).(2) The influence of AN to mice sperm quality parameters:①Sperm density in 14d group decreased obviously in each dose group of AN.②Sperm vitality in 14d group increased obviously in each dose group of AN.③Sperm living rate in 14d group increased obviously in each dose group of AN.④Sperm motility:a sperm motility increased obviously in 14d group while decreased in 21d group in AN1.25mg/kg group;Which increased obviously in 14d group while decreased in 28d group in AN2.50mg/kg and 5.00mg/kg groups.b sperm motility decreased obviously in 7d group and increased in 35d group in each dose group of AN.c sperm motility in all observation times had little variation amplitude in each dose group of AN.d sperm motility decreased obviously in 14d group and increased in 7d and 21d groups in AN 1.25mg/kg;Which decreased obviously in 14d and 35d groups in AN2.50mg/kg;It decreased obviously in 35d and 14d groups and increased in 7d group in AN 5.00mg/kg.⑤Sperm movement speed parametersr:In AN1.25mg/kg group,VAP and VSL increased obviously in 7d and 14d groups while decreased in 21d,and VCL had little variation amplitude in all observation times;VAP,VCL and VSL increased obviously in 7d group in AN2.50mg/kg and AN5.00mg/kg groups.⑥Sperm movement way parameters:LIN,STR and WOB had little variation amplitude in all observation times in each dose group of AN.⑦Sperm spatial displacement extent parameters:BCF and MAD had little variation amplitude in all observation times while ALH had relatively large amplitude in AN1.25mg/kg and AN2.50mg/kg groups;BCF and MAD had little variation amplitude in all observation times while ALH increased obviously in 7d in AN5.00mg/kg group.(3) The influence of AN to mice sperm mophorlogy:The sperm deformity rate increased significantly in 7d and 21d AN2.50mg/kg,7d and 28d AN5.00mg/kg,each dose group of AN in 14d and 35d (P<0.01);Head deformity was dominated in sperm deformity,the main types were amorphous and no hook.Compared with the negative control group,which had no statistic signifiance among every dose group(P>0.05).Conclusion (1) AN can induce Bcl-2 expression abate and Bax expression enhancement,especially in AN2.50mg/kg group;AN induce Bcl-2 and Bax expression changes,which may be one of the most important molecular mechanism of generative cell apoptosis. (2) AN can affect sperm density,vitality and living rate,especially variation amplitude is obvious in 14d;Mice sperm movement speed parameters and sperm motility with a certain degree of influence. (3) Teratogenic effect of AN was conspicuous,and the main types of sperm deformity were amorphous and no hook.