The Efficacy of Hyperbaric Oxygen for the Treatment of Experimental Uveitis Induced in Rabbits

Abstract

Objective: The aim of the present study was to examine the efficacy of hyperbaric oxygen (HBO) therapy in the treatment of experimental uveitis induced in rabbits. It was hypothesized that HBO therapy improves the regression of experimental uveitis induced in rabbits. Research design and methods: An experimental animal study was conducted on 48 rabbits (48 right eyes of these rabbits) to evaluate the effects of HBO therapy on endotoxin-induced acute anterior uveitis in rabbits. To induce acute anterior uveitis, Salmonella typhimurium lipopolysaccharide endotoxin (LPS) was intravitreally injected into the right eyes of the rabbits. The animals were randomly assigned to five groups. No treatment was given to the rabbits in Group A. Prednisolone acetate was topically administered to the rabbits in Group B. Methylprednisolone acetate was administered by anterior subtenon injection to the rabbits in Group C four hours after LPS application. HBO therapy was administered to the rabbits in Group D. Both HBO therapy and anterior subtenon injection of methylprednisolone therapy were administered to the rabbits in Group E. To compare the effects of the different therapies on the progression of endotoxin-induced uveitis, examinations including clinical scoring of anterior uveitis, microscopic examination of aspirated aqueous humor for inflammatory responses, and aqueous protein level assessment were performed once a day after LPS injection. Results: There was a statistically significant difference between the control group (Group A) and other groups (Groups B–E) with respect to the number of inflammatory cells and protein levels in the aqueous one and three days after LPS injection (p < 0.05), indicating that the treatments resulted in less inflammation in Groups B–E compared to Group A. Moreover, there was no statistically significant difference between Groups B and C, Groups B and D, Groups B and E, Groups C and D, and Groups C and E with regard to the number of inflammatory cells in the aqueous at Day 1 after LPS injection (p > 0.05). In addition, Groups B and C and Groups B and D were comparable with regard to cell counts at Day 3 (p > 0.05), showing that HBO was comparable to corticosteroids in reducing inflammation. The differences between Groups B and E and Groups C and E were significant with regard to aqueous cell counts at Day 3 (p < 0.05), showing that HBO plus steroid was more effective than steroids alone. Conclusion: The intensity of ocular inflammation in the group receiving HBO therapy combined with anterior subtenon injection of methylprednisolone therapy was lower than in the other groups. We also demonstrated that HBO therapy was an effective therapeutic modality for the treatment of experimental uveitis induced in rabbits with an efficacy comparable to that of corticosteroids. Moreover, HBO plus steroid was superior to steroids alone in reducing inflammation.