EFFECT OF DOXYCYCLINE HYCLATE ON CORNEAL EPITHELIAL WOUND-HEALING IN THE RABBIT ALKALI-BURN MODEL - PRELIMINARY-OBSERVATIONS

We examined the effects of doxycycline hyclate on epithelial healing i n vivo in the rabbit alkali-burn model. Twelve 2-3-kg Dutch belted rab bits were divided into three groups and received standard bilateral al kali burns (1 N sodium hydroxide for 30 s in an 11-mm circular plastic well). In group 1, two rabbits (four eyes) served as untreated contro ls. In group 2, five rabbits (10 eyes) received doxycycline hyclate (1 .5 mg/kg) orally daily for 14 days. In group 3, five rabbits (10 eyes) received doxycycline hyclate (5 mg/kg) orally daily for 14 days. The epithelial defects were drawn and photographed on alternate days, afte r fluorescein staining. At conclusion, extracts of the corneas were ev aluated for collagenase activity. At 14 days, the mean percentage of e pithelial defects results in groups 1-3 were 50.0, 50.7, and 7.1%, res pectively. Using the Wilcoxon rank sum test (two tailed), the differen ces were found to be statistically significant (p = 0.0015). Prelimina ry data indicated that oral doxycycline administration also decreased the collagenase activity in corneas obtained from these animals. Our p reliminary findings indicated that systematically administered doxycyc line hyclate, 5 mg/kg/day, promotes corneal reepithelialization in the rabbit alkali-burn model, a result, perhaps, of the drug's ability to inhibit excessive collagenase activity.