锌和维生素A对乙醇致大鼠睾丸损伤的保护作用

目的研究锌和维生素A（VA）对长期摄入乙醇致大鼠睾丸损害的保护作用及可能机制。方法 40只健康雄性成年SD大鼠随机分为对照组、乙醇组、乙醇＋葡萄糖酸锌组、乙醇＋VA组,每组10只,4组每日分别灌胃给予乙醇0、7.5g/kg、乙醇7.5g/kg＋葡萄糖酸锌7.7mg/kg、乙醇7.5g/kg＋VA50μg/kg,连续13周。对4组大鼠的精子计数、精子活动率、精子畸形率、血清睾酮（T）、黄体生成素（LH）、卵泡刺激素（FSH）含量进行检测,光、电镜观察睾丸的形态改变。同时测定睾丸线粒体中丙二醛（MDA）的产生量,免疫组织化学法检测睾丸组织中iNOS的表达。结果与对照组相比,乙醇组大鼠精子计数减少,精子活动率下降,精子畸形率升高（P〈0.05）,血清T、LH、FSH水平明显降低（P〈0.05）;睾丸生精上皮结构破坏,支持细胞和各级生精细胞均有退化变性;睾丸生精细胞iNOS表达明显增强（P〈0.05）;睾丸线粒体丙二醛含量明显升高（P〈0.05）。与乙醇组相比,乙醇＋葡萄糖酸锌组和乙醇＋VA组精子计数、精子活动率有所上升,生精细胞退化变性程度减轻,睾丸生精细胞iNOS表达减弱（P〈0.05）,睾丸线粒体MDA减少,但血清T、LH、FSH水平仍低于对照组（P〈0.05）。结论补充锌和VA可以限制乙醇引起的睾丸过氧化损伤,保护睾丸的生精功能,但仍有生殖内分泌激素合成障碍。

Protective effect of zinc and vitamin A on testis injury of rats induced by chronic alcohol intake

Objective To investigate the protective effect of zinc and vitamin A on testis injury of rats induced by chronic alcohol intake and its possible mechanism.Methods 40 healthy Sprague-Dawley adult male rats were randomly divided into 4 groups：control group,alcohol group（7.5g/kg）,alcohol＋zinc group（alcohol 7.5g/kg＋zinc gluconate 7.7mg/kg）,and alcohol＋vitamin A group（alcohol 7.5g/kg＋vitamin A 50μg/kg）.The alcohol,zinc gluconate and vitamin A were administrated to the rats for 13 weeks by a gastric tube.The sperm counting,motility and the percentage of abnormal sperm were observed.The serum sexual hormones（T,LH,FSH）were determined.The pathological changes of testicle tissue of rats were observed by light and electron microscopy.The malonaldehyde（MDA）contents in testicular mitochondria were simultaneously determined.The expression of iNOS in testes was detected by immunohistochemistry.Results As compared with control group,the sperm counting and motility in alcohol group were significantly decreased（P〈0.05）.The frequency of abnormal sperm was obviously increased（P〈0.05）.The serum levels of T,LH,FSH were significantly decreased（P〈0.05）.The MDA content and the expression of iNOS were markedly higher than those of control group（P〈0.05）.Histological evaluation for testes revealed that seminiferous epithelium was disorganized and the sertoli cells and germ cells were degenerated in alcohol-treated rats.Zinc or vitamin A supplementation decreased the testicular mitochondrial MDA formation and the expression of iNOS in testes,as a result,the germ cells degeneration was improved,sperm counting and motility were higher than those in alcohol group,however,which couldn＇t prevent the decrease of serum levels of sexual hormones（T,LH,FSH）（P〈0.05）.Conclusion Zinc or vitamin A supplementation limites the testicular peroxidation injury,which is a result of chronic alcohol exposure.To a certain degree zinc or vitamin A supplementation can protect the spermatogenesis function.