The effect of endothelin receptor antagonists in the endotoxin-induced uveitis rabbit model.

Purpose: To investigate the effect of Bosentan (non-selective endothelin receptor antagonist) and BQ123 (ET receptor antagonist) on intraocular inflammation in an endotoxin-induced uveitis (EIU) rabbit model.

Methods: Uveitis was induced by intravitreal injection of lipopolysaccharide (LPS). The animals were divided into 7 groups and there were six rabbits in each group (saline, saline and ethanol, bosentan, BQ123, lipopolysaccharide (LPS), bosentan and LPS, BQ123 and LPS-injected groups). Bosentan and BQ123 were applied before LPS injection. Aqueous humour was collected at 24th hour post-injections and enucleation was performed for the evaluation of histopathological changes.

Results: BQ123 decreased clinical score, cell counts and protein amount more than bosentan and it was significant for cell counts (p = 0.018). Bosentan significantly diminished inflammatory reactions more than BQ123 as shown in histopathological specimens (p = 0.002).

Conclusions: ET receptor blockage is effective on uveitis treatment by its protective effect on blood aqueous barrier.