Protective effect of berberine on renal fibrosis caused by diabetic nephropathy.

Berberine (BBR) is a material extracted from Chinese herbs, which has been used in the treatment of diabetes in Chinese medicine for thousands of years. However, the importance of BBR in renal fibrosis remains to be elucidated. In the present study, streptozotocin‑induced diabetic nephropathy (DN) rats were used to determine the effect of BBR on renal fibrosis. The pathology of the kidneys was examined using periodic acid‑Schiff (PAS) and Masson staining. The expression levels of transforming growth factor‑β (TGF‑β) and α smooth muscle actin (α‑SMA) in kidneys were observed using immunohistochemical staining. The mRNA and protein expression levels of TGF‑β, α‑SMA, vimentin, nuclear factor‑κB were examined using reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively. PAS and Masson staining revealed that there was notable glomerular hypertrophy and mesangial matrix expansion in DN rats. Immunohistochemistry revealed that there was a significant increase in TGF‑β and α‑SMA expression levels in the renal tubulointerstitium and the extracellular matrix. However, treatment with BBR may significantly reduce kidney injury. The protein and mRNA expression levels of TGF‑β, vimentin and α‑SMA were significantly increased in DN rats compared with the control group; however, this increase was reduced following treatment with BBR. The present study revealed that BBR may inhibit fibrosis and ameliorate the symptoms of DN. The current findings indicated that BBR may be used as a potential treatment for patients with DN.