Protective effect of berberine in diabetic nephropathy: A systematic review and meta-analysis revealing the mechanism of action

Coptis Chinensis Franch is widely used in the treatment of diabetes, and berberine is the primary bioactive component in it. Evidence from previous studies has shown that berberine supplementation is effective for treating diabetic nephropathy (DN) in animal models. In this systematic review and meta-analysis, we evaluated the effects and potential mechanisms of action of berberine in animal models of DN. Relevant studies were searched from the English language databases PubMed, Web of Science, and Embase starting from the establishment of the database till June 2022. Twenty-five studies were included, and the risk of bias tool from SYRCLE was used to assess the methodological quality. Statistical analysis was conducted using STATA 15.1. Fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (SCR), and the kidney index (KI) were the primary outcomes to be analyzed. The overall results showed that berberine improves the indicators of renal function, such as BUN, SCR, proteinuria, and KI. Meanwhile, berberine also improved inflammatory indicators, such as IL-6 and TNF-α, and oxidative stress indicators, such as the superoxide dismutase activity and malondialdehyde content. Additionally, berberine lowered the levels of known risk factors, including triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL). These beneficial effects of berberine in DN may be related to its anti-fibrotic, anti-inflammatory, and anti-oxidative stress properties. However, to assess the anti-diabetic nephropathy effects and safety of berberine in a more accurate manner, additional large-scale, long-term, and high-quality preclinical trials are needed to confirm these findings before clinical application.