The main study findings were: (i) the expression of miR−122−5p was most downregulated in fibrotic kidneys compared with control kidneys as assessed by microarray analysis; (ii) the injection of miR−122−5p promoted renal fibrosis and upregulated TGFBR2 (pro-fibrotic factor); and (iii) miR−122−5p suppressed renal fibrosis and upregulated FOXO3 and LC3 (anti-fibrotic factors). Here, FOXO3 is linked to renal fibrosis.