维生素C和B_1对铅致小鼠睾丸损伤保护作用研究

目的探讨维生素C、B1联合用药拮抗铅对睾丸的毒性作用。方法 1.30只雄性小鼠随机分为2组(15只/组):空白对照组和铅染毒组。染铅组雄性小鼠每日腹腔注射醋酸铅20 mg/kg,空白对照组给予等容量的生理盐水,一日一次,第42日结束以上实验。将小鼠取血,用试剂盒检测血浆中谷胱甘肽的含量、谷胱甘肽过氧化物酶(GPx)和谷胱甘肽还原酶(GR)的活性。将睾丸组织经过处理后,在光镜及透射电镜下观察睾丸组织结构变化;2.45只雄性小鼠随机分为3组(15只/组):空白对照组、铅染毒组和维生素联合干预组。染铅组雄性小鼠每日腹腔注射醋酸铅20 mg/kg,维生素干预组在染铅后,即时每组小鼠给予维生素C和维生素B1,一日一次,第42日结束。处死小鼠,取血,用试剂盒检测血浆中谷胱甘肽的含量,谷胱甘肽过氧化物酶(GPx)和谷胱甘肽还原酶(GR)的活性。在光镜以及透射电镜下观察睾丸组织结构变化。结果1.与空白对照组比较,醋酸铅染毒组小鼠血浆中还原型谷胱甘肽(GSH)的水平降低,GSH/GSSG的比例降低,GPX活性升高,GR活性降低;光镜下睾丸组织生精小管变薄,各级生精细胞、支持细胞减少,部分细胞核出现核固缩;3.电镜下染毒组小鼠睾丸组织超微结构变化明显,支持细胞溶酶体增多,线粒体肿胀空泡化;2.与醋酸铅染毒组比较,维生素干预组小鼠血浆中还原型谷胱甘肽(GSH)的水平升高,GSH/GSSG的比例升高,GPx活性降低,GR活性升高;光镜观察结果:与染铅组相比,维生素B1和C联合干预组中破坏的睾丸生精上皮有所恢复;电镜观察结果:与染铅组相比,维生素B1和C联合干预组睾丸组织超微结构基本恢复正常,生精细胞和支持细胞结构正常,细胞器丰富。结果 1.醋酸铅使体内GSH的水平降低,GPX活性升高,GR活性降低,从而诱导氧化应激的发生,导致染铅小鼠睾丸的损伤;2.维生素干预组小鼠血浆中还原型谷胱甘肽(GSH)的水平升高,GSH/GSSG的比例升高,GPx活性降低,GR活性升高,维生素干预组小鼠血浆中氧化型谷胱甘肽还原为还原型谷胱甘肽,从而发挥抗氧化作用,对小鼠睾丸起到保护作用。

PROTECTIVE EFFECT OF ASCORBIC ACID AND THIAMINE SUPPLEMENTATION AGAINST DAMAGE CAUSED BY LEAD IN TESTES OF MICE

Objective To investigate the protective effect and apoptosis-related mechanism of ascorbic acid and thiamine supplementation against damage caused by lead in the testes of mice.Methods 1.30 male mice were randomly assigned into 2 groups（15/group）：（1）Control group： Animals served as negative controls and received tap water alone;（2）Pb-treated group： Animals were treated with Pb（20 mg/kg） and received lead acetate by intraperitoneal injection daily.All the mice were anaesthetized with ether and killed by cervical dislocation on the 42nd test day.The activity of GPx and GR in the plasma were determined with activity assay kits according to the manufacture′s instructions.Under light microscope and transmission electron microscope（TEM）,cytoarchitecture changes of specimens stained with hematoxylin and eosin（HE） were observed.2.45 male mice were randomly assigned into 3 groups（15/group）：（1）Control group： Animals served as negative controls and received tap water alone;（2）Pb-treated group： Animals were treated with Pb（20 mg/kg） and received lead acetate by intraperitoneal injection daily;（3） Vitamin-protected group： Animals were injected VitC 420 mg/kg combined with VitB1 30 mg/kg daily afer Pb treatment.Bood was collected in tubes containing ethylene diamine tetraacetic acid as anticoagulant,the level of glutathione was measured using a glutathone assay kit.The activity of GPx and GR in the plasma was determined with activity assay kits.Testes were fixed in cold fixative for 48 h,and then paraffin sections were made.Under light microscope and transmission electron microscope（TEM）,cytoarchitecture changes of specimens stained were observed.Results 1.The GSH level in the Pb-treated group decreased compared with that of the control goup,GSH/GSSG ratio also decreased,and the activity of GPx increased while that of GR decreased.Under light microscopy,many seminiferous tubules became thin,and disappearance of most spermatids and spermatozoa was also observed in the Pb-teated group.Under TEM,the testis ultrastructure of the Pb-treated group changed significantly,with increased lysosome of sertoli cells and swelling and vacuolization of mitochondria.2.The GSH level in the vitamin-protected group increased when compared with that of the Pb-treated goup,GSH/GSSG ratio also increased,and the activity of GPx decreased while that of GR increased.Under light microscopy,the pathologic changes in seminiferous tubules had partly recovered,and some displayed a full spermatogenic component.Under TEM,the testis ultrastructure in mice exposed to vitamin B1 and C returned to normal testicular tissue,germ cells and Sertoli cells were normal,and organelles were rich in spermatogonia.Conclusion 1.The GSH level in the Pb-treated group decreased,GSH/GSSG ratio decreased,the activity of GPx increased while the activity of GR decreased,which may induce oxidative stress.2.The GSH level in the vitamin-protected group increased,GSH/GSSG ratio increased,the activity of GPx decreased while the activity of GR increased.GSSG is converted to the reduced form（GSH） by vitamin B1 and C.