Acupuncture attenuates renal interstitial fibrosis via the TGF-β/Smad pathway

Acupuncture is one of the most useful tools in complimentary medicine, and has demonstrated potential value for treating chronic renal failure (CRF). However, the underlying mechanisms for its therapeutic effect remain unknown. In the present study, the effects of acupuncture on renal interstitial fibrosis (RIF) were explored in a rabbit model of CRF. Rabbits were assigned to the following five groups: sham, model, losartan potassium (Posi), acupuncture (Acup) and acupuncture+inhibitor (Acup+Inhib) groups. The CRF rabbits were administered a drug or/and acupuncture on Shenshu, Mingmen and Pishu. The body weights, urine protein, serum creatinine (SCr) and blood urea nitrogen (BUN) levels of the rabbits were measured. Transforming growth factor beta (TGF-beta), integrin-linked kinase (ILK) and Smad3 expression were detected by qRT-PCR. Tumor necrosis factor-alpha (TNF-alpha) and endothelial nitric oxide synthase (eNOS) expression were analyzed by western blot methods. The concentrations of TGF-beta, IL-8, TNF-alpha and IL-1 beta in blood serum were detected using ELISA kits. In addition, pathological characteristics of the rabbit tissues were evaluated by H&E and Masson's trichrome staining methods, and TGF-beta expression was detected by immunohistochemistry (IHC) assays. Results showing decreased body weights and increased urine protein, SCr and BUN levels confirmed that the CRF model had been successfully constructed. It was also found that acupuncture significantly reduced the levels of TNF-alpha, Smad3, ILK and TGF-beta expression, dramatically decreased the concentrations of TGF-beta, IL-8, TNF-alpha and IL-1 beta in blood serum, and significantly increased eNOS expression in the CRF model rabbits by affecting the TGF-beta/Smad signaling pathway. In addition, it was demonstrated that acupuncture could relieve RIF by affecting the TGF-beta/Smad pathway. These observations indicate that acupuncture may be useful for treating CRF, and suggest the TGF-beta/Smad pathway as a target for CRF therapy.