The purpose of our study was to determine 1) the role of TLR4 in oxidative stress induction in the hypertensive kidney, 2) whether TLR4 induced oxidative stress leads to macrophage recruitment and inflammation, 3) whether TLR4 deficiency abrogates the effects above and inhibits fibroblast accumulation to reduce renal fibrosis. The gene discussed is TLR4; the disease is renal fibrosis.