Effects of estrogen and androgen on lens oxidative damage after ovariectomy in rat

Background Epidemiological investigation in human has been conclusive. In postmenopausal women,the incidence of cataract is higher than men at the same age. In addition,hormone replacement therapy may protect against the development of cataract. However,this role of androgen is not clear. Objective This study was to explore the effects of estrogen and androgen on anti-oxidative ability of lens after ovariectomy. Methods Fifty-six three-month-old clean female Wistar rats were randomly divided into normal control group,sham operation group, castration group,estrogen eyedrops group;estrogen injection group;androgen eyedrops group;androgen injection group and 8 rats for each. Ovariectomy was performed in the rats of castration group and gonadal hormone application group, and estradiol benzoate solution or testosterone propionate solution were utilized topically or systemly in 5 months after ovariectomy for 6 weeks respectively. Only abdominal cut was curried out in sham operation group. The lenses of rats were examined weekly under the slit lamp. The serum estrogen and androgen levels of rats were detected before,after operation and 6 weeks following the administration of gonadal hormone. The contents of superoxide dismutase( SOD) , glutathione( GSH) ,malondialdehyde( MDA) and water-soluble protein ( WSP) in rat lens homogenate were detected at the end of the experiment. Utilization of animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results No opacity of lenses was found during the experiment duration in various groups. The serum estradiol levels of rats in sham group were insignificantly different from normal groups in various time points( P>0. 05). The evident decline of serum estradiol was detected in the rats of castration group and gonadal hormone application groups compared with sham group in 5 months after operation( all P<0. 01). However,at the sixth weeks after the system use of estradiol or testosterone,the serum estradiol levels were significantly higher than the castration group and topical application groups of gonadal hormone(P<0. 01). The contents of SOD,GSH and WSP in lenses were considerably increased,but the MDA level in lenses was decreased after system use of estrogen ( P<0. 01). The activity of SOD and GSH were lower after system use of testosterone in comparison with castration rats ( P < 0. 05 ). Conclusion Estrogen can protect lens against oxidation damage. However, androgen, to a certain extent, may contribute to the development of oxidative damage in OVX female rats. Key words: Estrogen;  Androgen;  Ovariectomy;  Lens;  Oxidative damage