氧自由基在实验性角膜炎中的作用

The role of oxygen free radical in experimental keratitis

目的探讨氧自由基在角膜炎症过程中的作用。方法将新西兰白兔用脂多糖介导建立动物角膜炎模型，分别用化学发光法和硫代巴比妥酸比色法测定角膜组织超氧化物歧化酶（ｓｕｐｅｒ－ｏｘｉｄｅｄｉｓｍｕｔａｓｅ，ＳＯＤ）活力和丙二醛（ｍａｌｏｎｄｉａｌｄｅｈｙｄｅ，ＭＤＡ）水平的变化，观察其临床和病理变化。结果炎症组角膜ＳＯＤ活力明显低于对照组（Ｐ＜０．００１），ＭＤＡ水平高于对照组（Ｐ＝０．００１），炎症组角膜ＭＤＡ水平的升高发生于ＳＯＤ活力下降之后。角膜炎症状的轻重程度与角膜ＳＯＤ的活力呈负相关（ｒ＝－０．９５４，Ｐ＜０．００１），与角膜ＭＤＡ水平呈正相关（ｒ＝０．７３４，Ｐ＜０．００１）。结论氧自由基在角膜炎症过程中起着重要作用，并可能通过生物膜中多聚不饱和脂肪酸产生脂质过氧化而损害角膜。

Objective To test a possible role of oxygen species in corneal inflammation.Methods A keratitis model was inducde by an intrastromal injection of lipoplysaccharide （LPS） in one eye of Mew Zealand albio rabbits.During the imflam mation process, the activity of corneal superoxide dismutase （SOD）, an enzynatic scavenger of the superoxide free radical, wsa measured superoxid by chemolum inescent test,the level of cormeal malonaldehyde （MDA）,the final product of lipid peroxidation, was determinde by thiobtbituric acid test, and the clinical sand histopathological changes in cormea were observde.All the results of inflam matory cornea were compared with that of saline injected cornea.Results It was found that：（1）Singificant decrease in SOD activity （P〈0.001）and increase in MDA level （P=0.001） were observde in inflammation was negatively correlated with the conrtols.In the period of corneal inflammation,the increase in MDA level occurred after the decarade in SOD activity .（2）The severity of corneal inflammation was negatively correlated with the corneal SOD activity （r=-0.954,P〈0.001）and positively with corneal MDA level （r=0.734,P〈0.001）.Also a statistically significant negative correlation existed between SODactivity and MDA level in the imflammatory cornea（R=-0.623,P〈0.001）.Conclusion These findings suggest that active oxygen species play a role in LPS-inducde kreatitis and cause corneal injury by lipid peroxidation rtactions on the polyunsaturated fatty acid of biological membranes.