Figure 4: Quercetin suppresses the overexpression of TLR4 and the overactivation of NF-κB p65 induced by sustained hyperglycemia in a HO-1-dependent manner. (A) Western blot assay of TLR4 expression in retinal tissue. (B) Determination of NF-κB p65 activity in retinal tissue. Data are expressed as the mean ± SD (n = 10). *P < 0.05, **P < 0.01 (one-way analysis of variance followed by the Kruskal-Wallis test for multiple comparison). NF-κB: Nuclear factor-kappaB Q: quercetin; STZ: streptozocin; TLR4: Toll-like receptor 4; Znpp: zinc protoporphyrin IX.