抗氧化剂对准分子激光兔角膜切削术后角膜组织的影响

目的 探讨局部应用抗氧化剂VitC、VitE对准分子激光屈光性角膜切削术(PRK)术后角膜组织的影响。方法 将24只实验免分成2组，每组12只，行双眼一5．0DPRK。一组术后左眼每日结膜下注射VitC0．1g，右眼为对照；另一组术后左眼每日结膜下注射VitE25mg，有眼为对照。于术后1、3、7、14天测定角膜组织超氧化物歧酶(super—oxide dismutase，SOD)、丙二醛(malondialdehyde，MDA)及谷肮甘肽过氧化物酶(glutathioneperoxNe，GSH—PX)的变化，观察其病理变化。结果 术后1、3天角膜SOD、GSH—Px活性小于对照组(P＜0．01)，MDA的水平高于对照组(P＜0．01)。局部应用抗氧化剂组其角膜SOD、GSH—PX活性高于单纯激光组(P＜0．01)，MDA水平低于单纯激光组(P＜0．01)。结论 准分子激光屈光性角膜切削术后，存在着氧自由基性的组织损伤破坏，局部应用VitC、VitE能降低角膜的自由基损伤。

Effect of antioxidants in the rabbit cornea after photorefractive keratectomy

Objective To investigate the effect of topical antioxidants vitamin C, vitamin E on cornea tissue after photorefractive keratectomy. Methods 24 experimental rabbits were divided into 2 groups,each consisting of 12 animals. They were undergone bilateral PRK to correct 5 diopters of myopia. Following the trea tment, the left eye of each rabbit in one group was given subconjunctival injec tion with vitamin C 0 1 every day. The right eyes served as controls. In the ot her group the left eyes of each rabbit was given subconjunctival injection with vitamin E 25 mg every day. The right eyes served as controls. Rabbits were kille d at 1,3,7 and 14 days respectively,then measured the activity of corneal supero xide dismutase(SOD) and glutathioneperoxide(GSH PX), the level of corneal malon dialdehyde(MDA), and observed histopathological changes in cornea. Resul ts We found significant decrease in SOD, GSH PX activity( P< 0 01) and increase in MDA level( P< 0 01) compared with the control following 1,3 days after PRK. But the corneal S OD, GSH PX activity in antioxidants group was significantly higher than that of PRK group. The level of MDA in of antioxidants group was significantly lower th an that of PRK group. Conclusion Free oxygen radical causes tiss ue damage in the cornea after PRK. Topical vitamin C or vitamin E application de creases oxygen radical tissue damage after excimer laser corneal surgery.