To precisely understand the role of miR-122-5p in DKD, the effects of a miR-122-5p mimic were tested in streptozotocin (STZ)-induced diabetic nephropathy (DN) mice, and it was observed that the miR-122-5p mimic attenuated the tubular damage and interstitial fibrosis in DN mice, reduced the expression levels of urinary N-acetyl-β-d-glucosaminidase (NAG) as well as of the albumin-to-creatinine ratio (ACR), and diminished the expression levels of collagen I and vimentin. The gene discussed is ALB; the disease is diabetic kidney disease.