| As the number of aphoria patients increasing and more and more people begin to pay attention to reproductive health. As a representative of polycyclic aromatic substance, benzo[a]pyrene is a organic matter which have reproductive toxicity. Study on the PAHs on reproductive toxicity revealed that B[a]P exposure can cause testis semen volume, sperm count and sperm viability reduce. B[a]P can induce reproductive system damage by oxidative stress and DNA damage. Vitamin E is the most fat-soluble antioxidants of body. It can react with oxygen free radicals and interrupt the lipid peroxidation chain reaction. Some studies have reported that vitamin E can increase the quality of men’s sperm by promoting hormone secretion. ATP enzymes is the important information and energy transfer material in body. The level of ATP activity will affect the content of Ca2+. ATP enzymes activity decreased can cause content of Ca2+ in intracellular overload. The content of Ca2+ overload will lead to metabolic disorders of membrane in cells by phospholipid degradation and energy production reduction of mitochondrial. Children and worker who occupational exposure with PAHs are high-risk groups of PAHs. There are no drugs can prevent the damage caused by PAHs currently. Therefore, this study was to investigate whether or not vitamin E could antagonism the reproductive toxicity caused by B[a]P of male SD rats, and what is the mechanism in antagonism action.Object:Based on the previous study about reproductive toxicity in male SD rats which B[a]P exposure, we studied the vitamin E whether or not could ease of the reproductive damage. And we studied the testes damage of B[a]P by analyzing the change of the release of ATP activity and Ca concentration in rats. With different doses of vitamin E, we could to exploration whether there is a dose-response relationship with the vitamin E and B[a]P.Methods:60 SD male rats were randomly divided into 6 groups, including control group, solvent control group, B[a]P group, lower dose vitamin E+B[a]P group, medium dose vitamin E+B[a]P group and high dose vitamin E+B[a]P group. The rats were administrated intragastrically with the dose of 5mg/kg of B[a]P and with the dose of 10 mg/kg,50 mg/kg, 100 mg/kg of vitamin E respectively for 30 days. B[a]P was dissolved in olive oil, and the solvent control group was given the same amount of olive oil. Observation the change of sperm quality and testis organ coefficient on testis, to investigate the effect of B[a]P exposure on reproductive damage. Commercial kits were used to measure the level of 8-OHdG and MDA, the activity of SOD、GSH-Px and ATPase. Ca2+ concentration was measured by fluorescent labeling. The testicular tissue morphology and DNA damage in testicular cells were observed by HE staining and comet assay respectively.Results:1.1) Compared with the control group, the testis organ coefficient, sperm count and sperm activity was significantly reduced in B[a]P group, and the significant increase in sperm deformity rate.2)The study result showed that the sperm quality and testis organ coefficient in middle and high-doses vitamin E groups increased significantly compared to B[a]P group. In this study the low-dose vitamin E can’t antagonize B[a]P in reproductive damage.3) The result of HE staining showed that a number of spermatogenic cells of testis in B[a]P group had significantly reduced compared to control group. With increasing doses of vitamin E, the number of spermatogenic cells was significantly increased. Vitamin E can effectively alleviate the germ cell damage.2.Compared with B[a]P group, the concentration of SOD and GSH-Px significantly increased, and the concentration of MDA and 8-OHdG significantly decreased in control group, medium dose vitamin E and high dose vitamin E group.3 Commercial kits result shown that the expression of Ca2+-Mg2+-ATP enzyme activity and Na+-K+-ATP enzyme activity of testis in B[a]P exposure group was significantly difference compared to control group,50 mg/kg dose and 100mg/kg dose vitamin E groups, but no significant difference compared to 10 mg/kg dose vitamin E group. Calcium fluorescence quantitative detection result shown that Ca2+ concentration in B[a]P exposure group increased significantly compared to control group, 50 mg/kg dose vitamin E group and 100mg/kg dose vitamin E group. Comet assay result shown increased expression of the number of comet cells in B[a]P-exposed group. With the increasing doses of vitamin E, the number of comets cells reduced.Conclution:1.Damage of reproductive system in male rate mau due to several mechanisms:1).B[a]P can increase the number of oxygen radicals in testis, the oxygen radicals can oxidized the testis tissue, so that the oxidative damage produced.2) Germ cells DNA damage caused by oxidative in testis tissue.3) The damage of testis tissue is related to decrease of ATPase activity and increase of the calcium ion concentration. 2.1) Vitamin E can effectively slow down the B[a]P-induced genital lesions. 2) 50mg/kg/d and 100mg/kg/d doses of vitamin E have a good antagonize effect on 5mg/kg dose of B[a]P. |
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