Abstract
Abstract: :
Purpose: To examine the effect of topical administration of a matrix metalloproteinase inhibitor (MMPI) on collagenolytic/gelatinolytic activity in alkali-burned rabbit cornea. Methods: A central cornea (6 mm in diameter) of albino rabbits was exposed to a 1N NaOH for 3 min. The MMPI (GM6001, 0.5 mg/0.5 ml) was administered by subconjunctival injection and allowed to heal for 7 (n=3) or 14 (n=3) days. Vehicle was administered in control animals (n=6). Cryosections of affected corneas were histologically observed by HE staining and immunohistochemistry as well as were mounted onto gelatin film (in the presence or absence of another MMPI) and incubated at 37°C for 24 hr, and dried at room temperature. After drying, tissues were stained with Biebrich Scarlet, and observed under light microscopy. Results: During healing intervals the basement membrane was degraded as revealed by type IV collagen alpha5 immunostaining. Examination by in situ zymography did not detect MMP activity in uninjured corneas, whereas degradation of gelatin coating was detected in regenerated central epithelium and anterior stroma of alkali-burned corneas at Days 7 and 14. Such gelatin degradation was not seen in gelatin film containing a MMP inhibitor. In burned corneas with subconjunctival MMPI gelatin degradation in in situ zymography was minimal, almost none, at both 7 and 14 days post-treatment. Conclusions; Subconjunctival administration of a MMPI suppresses collagenolytic/gelatinolytic activity in cornea during healing following an alkali burn, thus suggesting a clinical efficacy.
Keywords: wound healing • cornea: epithelium • cornea: stroma and keratocytes