Telmisartan attenuates peritoneal fibrosis via peroxisome proliferator-activated receptor-γ activation in rats

Peritoneal dialysis (PD) is an effective treatment for patients with end-stage renal diseases, but long-term continuous PD causes peritoneal fibrosis (PF). This study aims to evaluate the anti-fibrotic effect of telmisartan on a rat model of PF and to investigate the underlying mechanisms. Five-sixths kidney nephrectomy and PD were used to establish the PF rat model. Glucose (2.5%) was used to establish an in vitro model in rat peritoneal mesothelial cells (PMC). Haematoxylin-eosin staining was used to examine the structural alterations. Masson's trichrome staining was used to observe the tissue fibrosis in peritoneal membrane of rats. Real-time polymerase chain reaction was used to measure messenger RNA expressions of profibrotic factors. Western blotting was used to determine protein expressions of profibrotic factors, peroxisome proliferator-activated receptor-γ, and mitogen-activated protein kinases (MAPK). Results demonstrated that administration of telmisartan dose-dependently attenuated the thickening of the peritoneal membrane and the fibrosis induced by long-term PD fluid exposure in rats. In addition, telmisartan treatment inhibited the upregulation of profibrotic factors induced by PD in the peritoneum of rats and by high-concentration glucose in PMC. Telmisartan was also effective in inhibiting PD and high-concentration, glucose-induced phosphorylation of MAPK in the peritoneum and PMC. Furthermore, peroxisome proliferator-activated receptor-γ (PPARγ) inhibitor GW9662 blocked these protective effects of telmisartan in PMC. The results suggest that telmisartan is effective in attenuating PD-induced PF, and this effect may be associated with the inhibition of profibrotic factor expression and MAPK phosphorylation via PPARγ activation.