Experimental Study Of Ascorbic Acid And SOD Therapy For Corneal Thermal Burns

Purpose. We studied the effect of topical and systemic ascorbic acid on a rabbit model of corneal disorders produced by thermal burn.To investigate the use of large doses of ascorbic acid in the treatment of corneal ulceration with ascorbutic state produced by thermal burn.Methods. 55 New Zealand rabbits were als experiment objects.51 New Zealand rabbits (102 eyes) were used to make corneal thermal burn models. 4 New Zealand rabbits(8 eyes) were as control.The burned rabbits were randomly assigned to four groups. Group 1 consisted of untreated controls.Group 2 received subconjunctival injections with ascorbate solution daily. Group 3 received systemetic ascorbic acid plus subconjunctival injections daily. Group 4 received subconjunctival injection with SOD. Ascorbate level and the vitality of SOD and the contents of MDA were determined in aqueous humor on days1.7.14.21 after thermal burning.The cornea of each group were studied for histopathology on days 7.14.21. The content of polymorphonuclear leukocyte in cornea were analysed by computer image .Results. The ascorbate level in aqueous humor on days 1 .7. 14 .21 after thermal burning were not significantly altered with control(P>0.05).The incidence of ulceration and perforation was increased in rabbits treated with both topical and systemic ascorbic acid. Through measuring of free radical index, we found the vitality of SOD in aqueous treated with ascorbic acid waslower than that in untreated control. The vitality of SOD in aqueous treated with SOD was higher than that in untreated control,and the result of MDA was reverse. The infiltration by PMN is the heaviest on days 7.14.21 after thermal burning in rabbits treated with both topical and systemic ascorbic acid .The group with topic ascorbic acid came the second.The infiltration by PMN is the least on days 7.14.21 after thermal burning in rabbits with no treatment. (P<0.05)Conclusion. The results of our study revealed that the use of large doses of ascorbic acid in the treatment of ocular inflammatory conditions were unassociated with a scorbutic state.The treatment of SOD to rabbit eyes could reduce the oxidation of cornea and the contents of malondialdehyde(MDA) in aqueous was decreased.The treatment of SOD to rabbit eyes could decreased the inflammatory reaction of cornea.