The efficacy of systemic and intravitreal infliximab treatments in an endotoxin-induced uveitis model

Abstract

Purpose: To compare the efficacy of systemic and intravitreal infliximab treatments in an experimental endotoxin-induced uveitis (EIU) model.Methods: Twenty-eight white New Zealand rabbits were equally divided into 4 groups. Group 1 received an intravitreal injection of 0.1 cc saline, group 2 received an intravitreal injection of 2 µg/0.1 cc lipopolysaccharide (LPS), group 3 received an intravitreal injection of 2 µg/0.1 cc LPS and 2 mg/0.1 cc infliximab, and group 4 received intravitreal injection of 2 µg/0.1 cc LPS and intravenous injection of 5 mg/kg infliximab. Clinical, biochemical (aqueous and vitreous humour protein levels and TNF-α concentrations), and histopathological evaluations were performed.Results: The clinical examination score was lower in group 4 than in group 2 (p = 0.006); but there was no significant difference between groups 2 and 3 (Bonferroni correction, p = 0.016). No statistically significant difference was found among groups 2, 3, and 4 for aqueous humour protein levels (p > 0.05). Significantly higher aqueous humour concentrations of TNF-α was measured in group 3 comparing to both group 1 and 4 (p = 0.003 and p = 0.002, respectively). No significant difference was found in vitreous protein levels or TNF-α concentrations among all study groups (Bonferroni correction, p = 0.026 and p = 0.101, respectively). Histopathological evaluation of the uveal tissue and anterior chamber reaction revealed the highest inflammation in group 3 (p < 0.001). In group 4, histopathological evaluation of uveal tissue was lower than in groups 2 and 3 (p < 0.001 and p = 0.001, respectively); whereas there was no difference in anterior chamber inflammation between groups 2 and 4 (p = 1.00).Conclusion: Intravitreal 2 mg/0.1 cc infliximab injection exacerbated inflammation in an EIU model; whereas systemic infliximab treatment at a dose of 5 mg/kg suppressed inflammation effectively and rapidly.