The antiinflammatory effect of nordihydroguaiaretic acid in endotoxin induced uveitis in rabbits

Abstract

The authors evaluated the anti-inflammatory effect of nordihydroguaiaretic acid (NDGA) and dexamethasone on an endotoxin induced uveitis (EIU) model, in rabbits. Six groups of 12 rabbits were formed. In groups II to V a uveitis was induced by an intravitreal injection of 5 ul of saline, containing 10 ng of endotoxin of Salmonella typhi. In group I, which is considered as the control, an intravitreal injection of 5 ul of saline was given. Each group received a different treatment and the inflammatory reaction was evaluated after 24 hours, quantifying the following parameters: clinical scoring, cells, proteins, PGE2, LTB4 in the aqueous and histopathological scoring. Compared to group II (non treated), group VI (treated with intraperitoneal 2 mg/kg dexamethasone) showed a decrease of 61% of proteins and LTB4, and a decrease of more than 90% of the other parameters studied. All these differences are statistically significant (p < 0.001). In groups III (intraperitoneal NDGA 10 mg/kg), IV and V (NDGA 1% topically every two and four hours respectively), the proteins showed a change of less than 5.5% and the PGE2 was reduced to around 50% compared to group II; these changes are not statistically significant (p > 0.05). The authors observed an important and significant decrease of the other parameters when compared to group II (p < 0.001). It can be concluded that at the doses given here, NDGA shows an effective action on the lipoxygenase pathway without an increase of the production of PGE2.