腈菌唑不同对映体对丽斑麻蜥性腺系统的影响

Effects of Myclobutanil Enantiomers on the Gonadal System in Mongolia Racerunner(Eremias argus)

腈菌唑(myclobutanil,MT)是一种应用广泛的手性杀菌剂,其手性对映体为(+)-腈菌唑(MT1)和(-)-腈菌唑(MT2)。腈菌唑手性单体具有不同的生物活性,但很少有其对爬行动物的对应选择毒性研究。为了评估腈菌唑手性单体对丽斑麻蜴性腺系统的毒性影响,将MT1(50 mg·kg-1)和MT2(50 mg·kg-1)以经口灌胃方式分别暴露给蜥蜴28 d。暴露期间,记录观察蜥蜴体重、血液中性激素(睾酮T和雌二醇E2)浓度以及性腺相关基因(3β-HSD、17β-HSD、CYP11A、CYP17、CYP19A、ER-α和AR)的表达图谱的变化。在MT1暴露组中,蜥蜴体重在28 d出现明显下降。而在MT2暴露组中,蜥蜴体重没有明显变化。雄性蜥蜴在经过1 d的暴露后,E2浓度在MT1暴露组中明显下降,而在MT2暴露组中明显上升。这些结果表明了腈菌唑手性单体的对映选择性毒性。在MT2暴露14 d后,雌性蜥蜴中CYP19A基因的表达上调弥补了体内E2浓度的降低。在MT1暴露的14 d,蜥蜴卵巢中观察到的CYP11A和CYP17基因表达下调以及CYP19A基因表达不变的这一现象解释了蜥蜴血液中E2和T的浓度减少。这些结果表明:MT1和MT2暴露对蜥蜴体内性激素造成不同的影响,而这些影响会相应改变性腺相关基因的表达。综上所述,MT1和MT2对性腺系统具有潜在的内分泌干扰效应,可能对蜥蜴造成不同程度的生殖损伤。

Myclobutanil（MT） is a widely used chiral fungicide with two enantiomers（MT1 and MT2）.Although the enantiomers of MT differ in biological activity,little is known about their enantioselective toxicity on reptiles.To evaluate the toxic effects of MT1 and MT2 on the gonadal system,lizards（Eremias argus） were orally exposed to MT1（50 mg·kg^-1） and MT2（50 mg·kg^-1） for 28 days.During MT enantiomers＇ exposure,lizard body weight,concentrations of plasma sex steroid hormones,i.e.,testosterone（T）,17β-estradiol（E2）,and expression profilesof steroidogenic-related genes,including 3β-HSD,17β-HSD,CYP11 A,CYP17,CYP19A,ER-α and AR,were measured.In MT1 exposure group,the body weights of lizards were significantly decreased at 28 days,while little changes were found after MT2 exposure.After 1 day of exposure in male lizards,the E2 levels were significantly down-regulated by MT1,while the levels of E2 were significantly increased in MT2 exposure group.These phenomena indicated the enantioselective alterations of MT1 and MT2.Exposure to MT2 resulted in up-regulation of CYP19A gene in females at 14 days to compensate for the decrease of E2 level.Besides,down-regulation of CYP11 A,CYP17 gene and unchanged transcription of CYP19A gene were observed at 14 days in the ovary after MT1 exposure,which explained the observed decrease of E2 and T level.These results showed that MT1 and MT2 exposure would cause different effects on sex steroid hormones,which correspondingly altered the expression of steroidogenic-related genes.Above all,both MT1 and MT2 have the potential to disturb lizard gonadal system,which may cause varying degrees of reproductive injuries in lizards.