【摘要】 目的 探讨环境污染物PM_2.5和高脂高糖暴露对大鼠雄性生殖系统的毒性作用。方法 将40只3周龄SPF级Wistar雄性大鼠随机分为4组,每组10只,分别为对照组（普通饲料,洁净室内）、PM_2.5组(普通饲料,暴露PM_2.5)、高脂高糖组（高脂高糖饲料,洁净室内）、联合暴露组(高脂高糖饲料,暴露PM_2.5)。利用实时染毒柜进行PM_2.5染毒,染毒仓内PM_2.5浓度为室外浓度的8倍,每天染毒6 h,每周7 d,连续染毒8周。染毒结束后,处死大鼠,收集血清、睾丸和附睾组织。采用HE染色检测睾丸和附睾组织的病理学改变,采用CASA和考马斯亮蓝染色技术检测附睾尾精子数量、活力和形态,采用实时荧光定量PCR技术检测睾丸和附睾组织内炎症反应相关分子肿瘤坏死因子α（TNF-α）、白细胞介素1β（1L-1β）、白细胞介素6（1L-6）和白细胞介素17（1L-17）的转录水平,采用ELISA和实时荧光定量PCR技术检测血清睾酮水平和睾丸组织内睾酮合成相关基因类固醇生成急性调节蛋白（Star）、细胞色素P450家族成员（Cyp11a1）和17β羟基类固醇脱氢酶（17β-Hsd）的转录水平,利用免疫印迹技术检测生殖屏障结构相关分子Claudin1、Claudin3、Occludin和ZO-1的蛋白表达水平。结果 与对照组相比,高脂高糖组大鼠睾丸间质结构松散、生精小管管腔内可见少量未成熟精子细胞脱落,而PM_2.5组和联合暴露组睾丸间质肿胀充血、生精小管基膜损伤、生精上皮排列紊乱、管腔内可见大量未成熟精子细胞脱落。在附睾组织,PM_2.5组、高脂高糖组、联合暴露组均表现出不同程度损伤,包括管壁上皮细胞排列紊乱和管腔内精子大面积脱落减少。与对照组相比,PM_2.5、高脂高糖暴露均引起大鼠精液质量明显下降,差异有统计学意义（P<0.05）。PM_2.5和高脂高糖暴露在睾丸和附睾引起炎症反应,并抑制睾酮的合成和分泌。PM_2.5组、高脂高糖组、联合暴露组大鼠的睾丸和附睾组织内生殖屏障结构相关分子表达水平明显下降,差异有统计学意义（P<0.05）。结论 PM_2.5和高脂高糖暴露对大鼠雄性生殖系统有明显毒性作用,其机制可能是通过抑制睾酮合成与分泌引起生殖屏障结构损伤,并促进炎症反应,从而引起大鼠精子发生和成熟障碍,导致精液质量下降。更多还原

【Abstract】 Objective To understand the joint toxic effects of environmental pollutants PM_2.5 and high-fat/high-sugar exposure on the reproductive system of malerats.Methods Forty Wistar rats aged 3weeks were randomly divided into four groups,10 in each,the control groups（standard feed,clean room）,the PM_2.5-exposed group(standard chow plus PM_2.5 exposure),the highfat/high-sugar group（high-fat/high-sugar feed,clean room） and the PM_2.5 and high-fat/high-sugar exposure in combination group(high-fat/high-sugar feed plus PM_2.5 exposure).The PM_2.5 and combined exposure groups were exposed to PM_2.5 by using a PM_2.5 real-time exposure system at 8 times the outdoor PM_2.5 concentration for 8 consecutive weeks,6 hours per day for 7days.Then,the reproductive tissues and serum were collected at the end of the exposure period.Real-time quantitative PCR technique was used to detect the transcript levels of pro-inflammatory factors including tumor necrosis factor-alpha（TNF-α）,interleukin 1β（1L-1β）,interleukin 6（1L-6）,and interleukin 17（1L-17） in rat testicular and epididymal tissues.The expression levels of testosterone in rat serum and the transcript levels of testosterone synthesis-related molecules including steroidogenesis acute regulatory protein（Star）,cytochrome P450 family member（Cyp11a1）,and 17 β hydroxysteroid dehydrogenase（17β-Hsd）in rat testis were measured by ELISA and qPCR,respectively.Expression levels of the reproductive barrier proteins including Claudin1,Claudin3,Occludin,and ZO-1 were detected using western blot.Results Compared with the control group,the rats in the high-fat/high-sugar group had loose testicular structures and a small number of immature spermatozoa were seen to be shed in the lumen of the seminiferous tubules.The rats in the PM_2.5 and combined exposure groups had swollen and congested testicular interstitium,damaged basement membrane of the seminiferous tubules,disorganized spermatogenic epithelium,and a large number of immature spermatozoa shed in the lumen.In the epididymal tissue,the rats in the high-fat/high-sugar,PM_2.5and combined exposure groups exhibited varying degrees of epididymal damage,as shown by the irregular arrangement of the epithelium and a reduction in the number of tubular spermatozoa.In addition,the semen quality of rats in the PM_2.5,high-fat/high-sugar,and combined exposure groups were significantly lower compared to the control group（P<0.05）.PM_2.5 and high-fat/high-sugar exposures could cause an inflammatory response in the testis and epididymis and inhibit testosterone synthesis and secretion.The expression levels of reproductive barrier-related molecules were significantly decreased in testicular and epididymal tissues in the PM_2.5 and combined exposure groups compared to the control group（P<0.05）.Conclusion PM_2.5 and highfat/high-sugar exposures in combination have obvious toxic effects on the reproductive system of malerats,and it is related with structural damage of reproductive barrier induced by inhibiting the synthesis and secretion of testosterone and to promote an inflammatory response,leading to spermatogenesis dysfunction and semen quality decreasein rats.更多还原