哺乳期接触双酚A对子代小鼠睾丸线粒体的影响

Effects of bisphenol A exposure during lactation on testicular mitochondria in male mouse offspring

目的研究哺乳期母鼠暴露于双酚A(BPA)是否通过线粒体途径引起雄性仔鼠成年后睾丸的氧化损伤和凋亡。方法母鼠分娩后随机分为BPA高、中、低剂量组(50、5、0.01 mg/kg)和溶剂对照组。哺乳期内每天灌胃给药,仔鼠成年后取睾丸测定线粒体中丙二醛(MDA),琥珀酸脱氢酶(SDH),谷胱甘肽-过氧化物酶(GSHPX)和超氧化物歧化酶(SOD)的含量变化。Western blot检测睾丸内细胞色素c(Cyt C)及凋亡相关因子半胱氨酸天冬氨酸蛋白酶-3(caspase 3)和凋亡诱导因子(AIF)的表达。透射电镜观察睾丸细胞线粒体结构变化。结果 BPA组睾丸线粒体中MDA含量显著升高(P<0.05),SDH活性显著降低(P<0.05),中高剂量组SOD和GSHPx活性显著降低(P<0.05),Western blot结果显示Cyt C、caspase 3和AIF表达量均显著升高(P<0.05)。透射电镜观察中高剂量组各级生精细胞内出现线粒体肿胀,线粒体嵴模糊或消失。结论哺乳期接触一定剂量BPA可能通过线粒体途径诱导睾丸生精细胞的氧化损伤和凋亡,从而影响子代睾丸的发育。

Objective To study whether maternal bisphenol A （BPA） exposure during lactation stage will induce oxidative stress and apoptosis in male offspring＇ s testis by mitochondrial pathway. Methods After delivery, maternal mice were randomly divided into four groups, including high dose group （50 mg/kg） , medium dose group （5 mg/kg） , low dose group （0.01 mg/kg） and solvent control group. BPA were given daily by gavage to maternal mice during lactation stage. The pups were raised and sacrificed at PND 75. The effect of BPA exposure on the activity of testicular mitochondrial succinate dehydrogenase （SDH） , superoxide dismutase （SOD） , glutathione peroxidase （GSH-Px） and malondialdehyde （MDA） in male offspring were detected. The expressions of cytochrome C （Cyt C）, caspase 3 and apoptosis-inducing factor （AIF） in testes of male offspring were detected by Western blot. Changes of mitochondrial substructure in testicular cells were observed by transmission electron microscopy. Results The exposed mice had a significant decrease in the activities of testicular mitochondrial SDH （P 〈O. 05） in all groups and with notable decrease in the activities of GSH-Px and SOD in the high and medium-dose groups （P 〈 O. 05 ）. BPA also caused testicular mitochondrial MDA increased markedly （P 〈 O. 05）. Western blot showed that the expression levels of Cyt C, caspase 3 and AIF increased significantly in the testes of BPA-treated groups （P 〈 O. 05）. Under transmission electron microscopy, mitochondria swell, crests obscure and disappear were founded in the high and medium-dose groups. Conclusion During lactation stage, maternal exposed to BPA induce oxidative stress and apoptosis of testicular cells by possible mechanisms of mitochondrial pathway,which would cause adverse effects on the early development of testis.