Effect of propolis on endotoxin-induced uveitis in rabbits

To test the anti-inflammatory effect of propolis, a natural bee-produced compound, and compare it with corticosteroids for the treatment of endotoxin-induced uveitis (EIU).

EIU was produced in all rabbits by unilateral intravitreal injection of 2,000 ng Salmonella typhimurium endotoxin. The animals were then divided randomly into three groups as follows: group A received no treatment (control); group B received methylprednisolone (5 mg/0.1 mL) (positive control); and group C received propolis (5 mg/0.16 mL) by anterior sub-Tenon injection at the time of uveitis induction and at 4 and 8 hours after induction. Inflammation was evaluated by clinical manifestations and by measuring the protein concentration and inflammatory cell content of the aqueous humor.

The clinical grade, cell count, and protein levels in the aqueous humor were: control group (6.0 +/- 0.8, 2,519 +/- 470 cells/microL, 32.9 +/- 2.4 mg/mL); methylprednisolone group (1.8 +/- 0.7, 572 +/- 137 cells/microL, 15.2 +/- 1.8 mg/mL); and propolis group (2.3 +/- 0.5, 503 +/- 124 cells/microL, 13.8 +/- 1.5 mg/mL). Statistically significant differences were recorded in the treatment groups when compared to the control group (P < .001). The effects of methylprednisolone and propolis on EIU were similar (P > .05).

Propolis showed significant anti-inflammatory effects on EIU in rabbits. The mechanism of its action warrants further investigation.