Topical Allopurinol or Corticosteroids and Acetylcysteine in the Early Treatment of Experimental Corneal Alkali Burns: A Pilot Study

Abstract

PURPOSE: To investigate the effect of topical allopurinol on experimental corneal burns and to compare this to established treatment modalities such as topical prednisolone and acetylcysteine. METHODS: Twenty Wistar rats were randomly assigned to four groups (n=5 each). The groups were controls (normal saline), allopurinol 0.4% eye drops, prednisolone acetate 1% eye drops and acetylcysteine 8% eyedrops. Corneal burn was induced using a 3 mm paper disc soaked in 1N NaOH for 60 seconds. Drops were instilled 6 times per day. In addition, one drop/day ofloxacine was given to prevent secondary infections. Eyes were enucleated 50 hours later and fixed in 4.5% formaldehyde. Three histological levels of each globe were stained with hematoxylin-eosin and examined by two independent masked investigators using a 0 to 4+ inflammatory score. All pair-wise multiple comparison procedures (Student-Newman-Keuls method) were applied for statistical work-up. RESULTS: All three substances significantly reduced the number of histologically visible inflammatory cells compared to the control group (p<0.05). CONCLUSIONS: In the present study, topical allopurinol was as effective as established drugs, namely steroids and acetylcysteine, in the early treatment of experimental alkali corneal burns.