吡氟酰草胺对大鼠睾丸的氧化损伤及机制研究

Oxidative Lesions and Mechanisms of Diflufenican on Rat Testis

目的:评价吡氟酰草胺原药对大鼠睾丸的损伤效应及其机制,为完善该新型除草剂的安全性评价及防护措施提供实验依据。方法:分别给予雄性SD大鼠0、20(低)、100(中)和500 mg/kg/d(高)的吡氟酰草胺连续经口染毒90天,观察其一般毒性表现;测定血清中谷胱甘肽(GSH)、总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)的含量;评价大鼠的睾丸损伤,采用免疫印迹法检测睾丸组织中Cleaved-caspases 3、C-PRAR、FAS/FASL等蛋白的表达,并运用免疫组化法进行验证。结果:与对照大鼠相比,中、高剂量组的吡氟酰草胺能明显降低大鼠的体重增长及食物利用率(P<0.05);血清SOD和T-AOC水平下降,以高剂量组SOD下降显著(P<0.05),但GSH未见变化;染毒大鼠睾丸的生精小管空泡化严重、管腔内精原细胞显著减少;低、高剂量组大鼠睾丸组织中Cleaved-caspases 3、C-PRAR、FAS的表达显著增加;免疫组化也证实,低、高剂量组染毒大鼠生精小管中Cleaved-caspases 3阳性的细胞数显著增加(P<0.05)。结论:吡氟酰草胺可引起大鼠睾丸中的抗氧化能力下降,睾丸可能是该除草剂潜在的靶器官,氧化应激通路可能参与了吡氟酰胺所致的雄性生殖毒性。

Objective： To study the adverse effect and mechanisms of diflufenican on rat testis, and try to provide the experimental evidence for improving the safety evaluation and protective measures of this new herbicide. Methods： Male SD adult rats had been given 0, 20, 100, 500 mg/kg of diflufenican for 90 days. The general toxicities were observed, and the serum GSH, T-AOC, SOD were measured, Besides, the pathological trauma of testis of rats was observed, and the protein expressions of Cleaved-caspases 3, C-PRAR, FAS/FASL in testicular tissue were detected by immunoblotting, and further validated by immunohistochemical assay. Results： Compared with control group, the middle and high doses of diflufenican groups obviously reduced the ponderal growth and food utility rate of rat （P〈0.05）, and depressed either serum SOD （P〈0.05） or T-AOC levels except for GSH. In addition, the pathological observation in contaminated rat testis showed the vacuolation in seminiferous tuble and spermatophore reduce in lumen. Subsequently, the expressions of Cleaved-caspases 3, C-PRAR, FAS in rat testis remarkably increased, which was confirmed by immunohistochemistry results that the Cleaved-caspases 3 positive cell population in rat seminiferous tubule obviously increased in low and high contamination groups （P〈0.05）. Conclusions： Diflufenican can decline oxidation resistance in rat testis, which indicated that the testis might be the potential target of this kind of herbicide. Oxidative stress pathway might contribute to the diflufenican-induced male reproductive toxicity.