Centella asiatica inhibits renal interstitial fibrosis by regulating Smad3 and Smad7 expression in the TGFβ signaling pathway

Centella asiatica (CA) is a well-known traditional Chinese herb with a long history of therapeutic uses. In the present study, we evaluated the effect of CA granula on renal interstitial fibrosis, as well as Smad3 and Smad7 in a TGF-beta signaling pathway mediated mechanism. Fifty adult SD male rats were randomly divided into five groups: sham-operated; unilateral ureteral obstruction (UUO); Monopril; high-dose CA (CA (H)); and low-dose CA (CA (L)). Blood samples were collected 14 days after oral gavage and the blood urea nitrogen (BUN) and serum creatinine (Scr) was measured. H&E and Masson straining were utilized to determine the renal tubule interstitial fibrosis. Smad3 and Smad7 mRNA and protein levels were determined in kidney tissues by immunohistochemistry, real-time PCR, and Western blot analysis respectively. Compared with the UUO group, the CA treatment significantly inhibited renal interstitial fibrosis and Smad3 expression, but increased Smad7 expression at both mRNA and protein levels in a dose-dependent manner. Our research suggests that CA administration could delay renal interstitial fibrosis by inhibiting Smad3 but promoting Smad7 expression in TGF-beta pathways, without obvious liver or kidney toxicity.