Anti-inflammatory effects of water-dispersible hesperetin on endotoxin-induced uveitis in rats involving the nuclear factor κB and Wnt/β-catenin signaling pathways.

Abstract

This study investigated the anti-inflammatory effects of water-dispersible hesperetin (WD-Hpt) in an endotoxin-induced uveitis (EIU) rat model. The rats were orally administered 10, 25, or 50 mg/kg WD-Hpt immediately after lipopolysaccharide (LPS) injection at the concentration of 200 μg. Clinical scores, cellular inflammation, the aqueous humor (ApH) protein concentration, as well as the levels of tumor necrosis factor (TNF)-α, cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) in AqH, and histopathological grades were assessed. Immunohistostaining and mRNA analyses measured expressions of TNF-α, COX-2, iNOS, activated nuclear factor (NF)-κB p65, I kappa B (IκB)-α degradation, phosphorylated (p)-IκB kinase (IKK) α/β, β-catenin, and glycogen synthase kinase (GSK)-3β. Compared to LPS treated group (LPS txg), WD-Hpt treatment groups (WD-Hpt txg) resulted in the following results: 1) clinical scores improved [LPS txg; 3.90 ± 0.20, WD-Hpt txg; 2.40 ± 0.37 (P<0.05)], 2) the number of inflammatory cells in AqH decreased [LPS txg; 8.65 ± 1.41 × 105 cells/mL, WD-Hpt txg; 3.83 ± 1.20 × 105 cells/mL (P<0.05)], 3) AqH protein concentration reduced [LPS txg; 36.65 ± 2.71 mg/mL, WD-Hpt txg; 28.73 ± 2.36 mg/mL (P<0.05)], and 4) decreased levels of TNF-α [LPS txg; 69.55 ± 7.38 pg/mL, WD-Hpt txg; 35.18 ± 9.22 pg/mL (P<0.001)], iNOS [LPS txg; 153.37 ± 12.72 μM, WD-Hpt txg; 110.79 ± 13.27 μM (P<0.05)], and COX-2 [LPS txg; 1,080.56 ± 196.06 pg/mL, WD-Hpt txg; 477.80 ± 66.61 pg/mL (P<0.01)] in AqH were observed, and histopathological grades improved [LPS txg; 2.80 ± 0.40, WD-Hpt txg; 1.50 ± 0.50 (P<0.05)]. Immunostaining and mRNA analysis revealed that 50 mg/kg WD-Hpt effectively suppressed iNOS, COX-2, NF-κB p65, IκB-α degradation, p-IKKα/β, β-catenin, and GSK-3β expression. These findings suggested that WD-Hpt exerts anti-inflammatory effects by targeting the NF-κB and Wnt/β-catenin pathways.