DEHP对新生雄性仔鼠毒性作用的实验研究

目的探讨邻苯二甲酸二乙基己基酯(DEHP)对新生雄性仔鼠毒性作用及机制。方法 DEHP分别以低、中、高3组剂量10、100、750mg/(kg.d)]灌胃作用于怀孕12天到产后21天(GD12～PND21)的SD母鼠,观察DEHP对产后1天(PND1)及产后21天(PND21)雄性仔鼠体重、睾丸重量、肛生殖器距离(AGD)和其对胚胎Leydig细胞形态结构、促黄体生成素受体(LHR)及类固醇激素合成急性调节蛋白(StAR)的蛋白表达水平的影响。结果 PND1中、高剂量组雄仔鼠的体重下降明显,分别与对照组和低剂量组相比较均有显著性差异(P<0.01);高剂量组睾丸重量下降明显,与对照组相比较有显著性差异(P<0.05);中、高剂量组雄仔鼠的AGD均有不同程度缩短,与对照组和低剂量组相比缩短均有显著性差异(P<0.01)。PND21中、高剂量组雄仔鼠的体重下降明显,分别与对照组和低剂量组相比均有显著性差异(P<0.01);高剂量组睾丸重量下降明显,与对照组相比有显著性差异(P<0.01);中、高剂量组雄仔鼠的AGD缩短明显,分别与对照组比较有显著性差异(P<0.01)。光镜下低剂量组可见胚胎Leydig细胞(FLC)聚集呈簇分布,中剂量组与高剂量组均可见胚胎Leydig细胞呈瘤样增生。电镜示低剂量组Leydig细胞椭圆形、长梭形,脂质颗粒减少,线粒体、滑面内质网丰富。中、高剂量组Leydig细胞呈梭形或椭圆形,大小不一,核大、圆,胞质丰富,细胞聚集一起,胞质内可见丰富的脂质颗粒,脂质颗粒染色深,滑面内质网及线粒体扩张。中、高剂量组睾丸FLC的LHR蛋白表达明显减弱,与对照组比较有显著性差异(P<0.01);高剂量组睾丸FLC的StAR蛋白表达减弱明显,与对照组比较有显著性差异(P<0.01)。结论 DEHP对新生雄性仔鼠具有毒性作用,其可能机制是DEHP宫内暴露后,抑制睾丸FLC的LHR蛋白和StAR蛋白的表达从而影响睾丸的发育。

Experimental Research of the Effects of DEHP on the Newborn Male Rats

Objective To explore the effects of di(2-ethylhexyl) phthalate(DEHP) on newborn male rats.Methods Pregnant Sprague-Dawley rats were exposed to DEHP at the dose of 10mg/kg(low dose group),100mg/kg(middle dose group) or 750mg/kg(high dose group)(body weight) per day by oral gavage from gestation day 12(GD12) through postnatal day 21(PND21) respectively.The body weight of male pups,testis weight,anogenital distance(AGD) and testicular histopathology were investigated.The protein expression of LH receptor(LHR),steroidogenic acute regulatory protein(StAR) was observed by immunohistochemistry.Results On PND1,the body weight of male pups from middle and high dose group was decreased significantly compared with control and low dose group(P<0.01).The testicular weight from high dose group was decreased significantly compared with control group(P<0.05).The AGD of male pups from middle and high dose group was shortened significantly(P<0.01) compared with control and low dose groups.On PND21,the body weight of male pups from middle and high dose group was decreased significantly(P<0.01) compared with control and low dose group.The testicular weight of male pups from high-dose group decreased significantly(P<0.01) compared with control group.The AGD of pups from the middle and high dose groups were shortened significantly(P<0.01) compared with control and low dose groups.Microscopically,FLCs from the lowdose group showed aggregation cluster distribution,while FLCs from middiledose and high dose groups manifestated as tumorlike hyperplasia.Under electron microscope,FLCs from lowdose group showed oval-shaped or long spindle-shaped,lipid particles was decreased,but smooth endoplasmic reticulum and mitochondria were increased in cytoplasm.In middle and high dose groups,FLCs were aggregated,cytoplasm were rich lipid particles,lipid particles were deep-staining,smooth endoplasmic reticulum and mitochondria were expanded.The protein expression of LHR in middle and high dose groups decreased significantly(P<0.01)compared with control group,the protein expression of StAR in high dose group decreased significantly(P<0.01) compared with control group.Conclusion DEHP may have toxicity in newborn male rats,it may interfer with the development of testis of male pub by inhibiting the expression of LHR and StAR.