Anti-inflammatory effect of Heliotropium indicum Linn on lipopolysaccharide-induced uveitis in New Zealand white rabbits.

Aim: To investigate the anti-inflammatory effect of an aqueous whole plant extract of Heliotropium indicum (HIE) on endotoxin-induced uveitis in New Zealand white rabbits.

Methods: Clinical signs of uveitis including flares, iris hyperemia and miosis, were sought for and scored in 1.0 mg/kg lipopolysaccharide (LPS) -induced uveitic rabbits treated orally with HIE (30-300 mg/kg), prednisolone (30 mg/kg), or normal saline (10 mL/kg). The number of polymorphonuclear neutrophils infiltrating, the protein concentration, as well as levels of tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), and monocyte chemmoattrant protein-1 (MCP-1) in the aqueous humor after the various treatments were also determined. A histopathological study of the anterior uveal was performed.

Results: The extract and prednisolone-treatment significantly reduced (P≤0.001) both the clinical scores of inflammation (1.0-1.8 compared to 4.40±0.40 in the normal saline-treated rabbits) and inflammatory cells infiltration. The level of protein, and the concentrations of TNF-α, PGE2 and MCP-1 in the aqueous humor were also significantly reduced (P≤0.001). Histopathological studies showed normal uveal morphology in the HIE and prednisolone-treated rabbits while normal saline-treated rabbits showed marked infiltration of inflammatory cells.

Conclusion: The HIE exhibits anti-inflammatory effect on LPS-induced uveitis possibly by reducing the production of pro-inflammatory mediators.