Effect of corticosteroids on the stromal dry mass in alkali-burned rabbit corneas

Abstract

Purpose. The effects of corticosteroids in alkali-burned corneas are controversial. The treatment in early period after tne alkali wound has been thought to be successful to some extent, but the strnmal healing takes many months after the initial injury. The purpose of this study is to evaluate the effect of corticosteroids on the stromal dry mass in alkali-burned rabbit corneas. Methods. A 5.5 mm round filter paper soaked in 1 N NaOH was applied on one eye of the 28 New Zealand white rabbits for 60 sec. In 14 rabbits, a single subconjunctival injection of methylprednisolone followed by topical administration of 0.1 % Dexamethasone 3 times a day was don;. At 1 week and 3 weeks, 7 rabbits in each group were sacrificied and corneal buttons were taken and freeze-sectioned and dried. After that, the sections mounted on a photographic emulsion were exposed to soft X-rays at 3 kV. The dry mass of the anterior, middle, and posterior stroma in each section of microradiography was evaulated microdensitometrically. RtSMUs- At 1 week, dry mass of anterior, middle and posterior stroma in steroid treated group and in control group wen: 0.134±0.04 (g cm -3) and 0.281±0.03 (g cm -3), 0.079±0.04 (g cm -3) and 0.242±0.03 (g cm -3), and 0.137±0.04 (g cm -3) and 0.254±0.02 (g cm -3), respectively. At 3 weeks, dry mass of anterior, midddle and posterior stroma in two groups w<:re 0.141±0.08 (g cm -3) and 0.184±0.05 (g cm -3), 0.103±0.04 (g cm -3) and 0.160±0.06 (g cm -3), and 0.141±0.05 (g cm -3) and 0.160±0.07 (g cm -3) Conclusions. The corticosteroids causes a reduction of dry mass in the anterior and posterior part of the stroma. In the middle stroma the dry mass content was higher in the steroid treated group.