NOS2 and chronic kidney disease: Samples with low fibrosis displayed a faint positivity for iNOS and less TGF-β1 positive cells, while the expression of both proteins was increased in those with advanced fibrosis.14,15 The iNOS knockout mice fed a high-cholesterol diet for 6 weeks exhibited significant reductions in hepatic fibrosis and expression of TGF-β.16 Similarly, considerable studies also highlighted the importance of iNOS in chronic kidney disease.17 The iNOS-deficient and antibiotic-treated WT mice exerted less fibrotic, which stated that iNOS played a crucial role in the process of renal fibrosis.18