TLR4 and metabolic syndrome: In this study, the elevated renal expression of TNF-α, as a pro-inflammatory marker together with upregulated TLR4 IHC expression in renal tissues of MetS rats, was consistent with a study by Hardy et al. who stated that MetS elevates the expression of TNF-α, TLR4, TLR2, and IL6 genes in peripheral monocytes of adolescents (6).