Study On The Reproductive Toxicity Induced By Acrylonitrile In Male Mice

Objective To explore the effect of acrylonitrile (AN) on the reproductive system and its mechanism in male mice in order to provide some theoretical data for protecting the health of occupational exposure population group induced by AN.Methods 250 health adult male mice of Kunming genera in SPF degree were randomly divided into five groups according to the body weight, including the exposure groups treated with AN intraperitoneally at dose of 1.25mg/kg,2.50mg/kg and 5.00 mg/kg respectively once a day for five days, the negative control group treated with normal saline in the same condition, but the positive control group treated with 40mg/kg cytoxan only for once in the same route of exposure, and the injected dose of all dose groups was 0.01ml/g.All mice were sacrificed in batch by cervical dislocation at the 7th,14th,21th,28th,35th day respectively after the first administration. Sperm movement parameters and the levels of testosterone (T), luteotrophic hormone (LH) and follicle-stimulating hormone (FSH) were measured with WLJY-9000 color-detection system of sperm quality and radioimmunoassay (RIA) respectively. lactate dehydrogenase(LDH), acid phosphatase(ACP), alkaline phosphatase(AKP),Malondialdehyde(MDA), superoxide dismutase(SOD), glutathione (GSH) and total antioxide capacity(T-AOC) in testicular homogenate were detected with spectrophotometric assay. The light microscope and electron microscope were used to observe the changes of histopathology and ultra structure of mice testis. The various ploidy cells and cell cycle of spermatogenic cells in mice testis were detected with Flow cytometry (FCM)Results (1) Comparison among the different AN exposure groups at the same observation time showed no obvious statistical significance in the sperm movement parameters (P>0.05). Comparison among the different groups of observation time in the same exposure group showed that the sperm density increased obviously in 7d group while decreased in 14d group, then the sperm motility decreased in 7d group and 21d group and increased in 14d group, but the motility rate of sperm increased in 14d group while decreased significantly in 21d group in AN 1.25mg/kg group. Motility of sperm and motility rate of sperm in 21d group increased obviously in AN 2.50mg/kg group. Sperm motility had some abnormal changes at the different observation times and motility rate of sperm in 7d group decreased obviously in AN 5.00mg/kg group.Then the content of T in 21d group was significantly decreased compared with negative control group in AN 2.50mg/kg group(P<0.05). (2) Comparison among different exposure groups at the same observation time, the results showed that the content of LDH in AN 1.25mg/kg group was significantly higher than that of other groups, and significantly decreased in AN2.50mg/kg group(P<0.01), then the level of ACP decreased significantly in AN 2.50mg/kg group (P<0.05), and the content of GSH in AN 2.50mg/kg and 5.00mg/kg groups were significantly higher than that of negative control group and AN 1.25mg/kg group(P<0.01) at the end of AN exposure 7th day. The activity of LDH in AN 5.00mg/kg group was significantly higher than that of negative control group(P<0.05), then the content of MDA in 2.50mg/kg group was significantly higher than that of other groups(P<0.01), but the level of T-AOC in 5.0mg/kg group was significantly higher than that of negative control group and AN 1.25mg/kg group(P<0.01) at the end of exposure 21th day. The content of GSH in AN 5.00mg/kg group was significantly decreased than that of negative control group(P<0.05) at the end of 28th day. Compared with negative control group, the content of MDA increased in all exposure groups of AN (P<0.05) and the activity of SOD inhibited by AN in all exposure group at the end of 35th day(P<0.05). Comparison among different groups of the observation time with the same exposure group, the results showed that the activity of LDH in 7d group and 14d group were inhibited and ACP activity decreased with the observation time elongation, but the levels of MDA and SOD in 21d group increased obviously in AN1.25mg/kg group. The activity of LDH in 7d group was higher than that of 28d group and 35d group, the activity of ACP in 7d group was inhibited and AKP activity in 28d and 35d groups decreased obviously, the levels of MDA and SOD increased obviously, but the level of GSH in 7d group decreased in AN2.50mg/kg group. The activity of LDH in 7d group showed abnormal change, the levels of AKP and SOD in 21d group and MDA in 35d group increased obviously and the activity of GSH in 7d group decreased in AN5.00mg/kg group. (3) The result of the light microscope in exposure groups showed the atrophy of seminiferous tubules, the number reduction of spermatogenic cells and spermatozoa in the seminiferous tubules, and presented the interstitial edema, alignment rarefaction, cell division abnormality, vacuolation and apoptotic cells in Leydig cells, but the abnormal changes of testis morphology observed obviously in the first 7 days under electron microscope, the results presented the growing in number of particles in Leydig cells, mitochondria swelling, reticulum dilated in sertoli cells, and appeared vacuolization in spermatids in all exposure groups.(4) Compared with control groups,the cell population of various ploidy, cell cycle and the ratios of different ploidy cells had no obvious abnormal changes in exposure groups(P> 0.05).Conclusion (1) The sperm movement parameters were more sensitive to AN at the beginning of AN exposure and the content of T in serum decreased. (2) The levels of testis marker enzymes indicated abnormal changes at the beginning of AN exposure and the damage of lipid peroxidation effect induced by AN enhanced in mice testis. (3) The some changes of histopathology and ultra-microstructure caused by AN were discovered in mice testis. (4) The cell cycle and the population of various ploidy in AN exposure groups didn't indicate any abnormal changes in mice testis.