TLR4 and diabetic kidney disease: Studies have shown that the renoprotective effect of icariin in DKD mice is mediated by the inhibition of renal toll-like receptor 4 (TLR4), p-NF-κB p65, TNF-α, and IL-6 expression, downregulation of the TLR4/NF-κB pathway, and attenuation of inflammatory responses.