新生期脂多糖暴露对大鼠睾丸发育及波形蛋白表达的影响

目的探讨新生期脂多糖暴露对睾丸发育及波形蛋白表达和分布的影响。方法选取新生雄性SD大鼠150只,随机分为对照组和实验组,实验组于生后第4～12d期间,隔日皮下注射脂多糖（75μg/kg）,共5次,对照组在相同时间皮下注射等容生理盐水。常规饲养至生后14d、21d、28d、包皮分离日、60d、77d分批取材,采用组织学和免疫组化技术,观察脂多糖对大鼠睾丸发育、波形蛋白的表达与分布的影响。结果①与同龄对照组相比,实验组大鼠生精小管横径变小,生精上皮变薄,细胞排列紊乱,生精细胞与支持细胞分离,脱落至管腔,性成熟以后,管腔内精子生成减少;②对照组波形蛋白阳性染色从基膜围绕支持细胞核形成棕黄色的环,并呈辐射状延伸至管腔;实验组支持细胞变矮、变圆,波形蛋白仅见于核周或核的基部胞质,伸向管腔的辐射状条带变短或消失。结论新生期脂多糖暴露,可改变支持细胞波形蛋白的有序分布,造成生精细胞脱落,干扰生精细胞的发育成熟,这种影响可延续至成年期,导致成年期精子生成减少。

Effect of neonatal lipopolysaccharide exposure on testicular development and vimentin expression of rats

Objective To investigate the effects of neonatal period lipopolysaccharide（LPS）exposure on testicular development and vimentin expression of rats.Methods A total of 150 neonatal Sprague-Dawley male rats were used in this study.The litters were randomly divided into either LPS-treated or saline control groups.These rats were administered 75ug/kg LPS or an equi-volume of non-pyrogenic saline via subcutaneous injection on alternate day from postnatal days 4 to 12.All the rats were then fed conventionally and sacrificed on PND14,PND21,PND28,Preputial separation,PND60 and PND77 respectively to collect the testis.The testicular morphology and vimentin expression were observed by histological and immunohistochemical methods respectively.Results ①Compared with saline control rats of the same age,LPS-treated rats exhibited a thinner spermatogenic epithelium and less tubular diameter.The percentage of tubules demonstrating structural irregularity significantly increased.The germ cells arranged in disorder and detached from Sertoli cells filling the lumen.The number of sperm was significantly reduced in adulthood.②In saline control rats,strong positive expression of vimentin was observed in the cytoplasm of Sertoli cells,the vimentin positive staining resulted in a Buffy ring surrounding the nucleus with elongating radially towards the lumen of seminiferous tubule.In LPS-treated rats,the Sertoli cell became shorter and round,a vimentin immunoreactivity was only seen in the cytoplasm surrounding Sertoli cell nuclei with shorten or no extending radiate filaments towards the tubular lumen.Conclusions Neonatal lipopolysaccharide exposure altered distribution of vimentin in Sertoli cells,caused spermatogenic cell displaced away from the basement membrance of seminiferous tubules,interfered with mature of spermatogenic cell and diminished sperm presence in adulthood.