[Effects of ginsenoside Rb1 on TGF-beta1 induced p47phox expression and extracellular matrix accumulation in rat renal tubular epethelial cells].

OBJECTIVE

To investigate the effects of Ginsenoside Rb1 (G-Rb1) on the oxidative damage and extracellular matrix accumulation in rat renal tubular epethelial cells induced by transforming growth factor-beta1 (TGF-beta1).

METHODS

Cultured normal rat renal tubular epethelial cells (NRK-52E) were divided into control group, 10 ng/mL TGF-beta1-induced group, G-Rb1 treated groups in which rat renal tubular epethelial cells were treated with different concentration of G-Rb1 (10 ng/mL, 20 ng/mL, 40 ng/mL) after TGF-beta1 induction, G-Rb1 40 ng/mL group and 100 nmol/L DPI(diphenyleneiodonium, an inhibitor of NADPH oxidase) group. Intracellular reactive oxidative species (ROS) level was measured by flowcytometry. p47phox protein expression was assessed by immunohistochemistry and western blotting method. The expressions of collagen I (Col-I) and fibronectin(FN) gene were measured by real-time PCR analysis. The protein level of Col-I and FN were quantitatively detected by enzyme-linked immunosorbent assay.

RESULTS

TGF-beta1 at 10 ng/mL significantly increased the intercellular ROS production and p47phox expression (P < 0.05). The levels of Col-I and FN were also significantly up-regulated with the stimulation of 10 ng/mL TGF-beta1 (P < 0.05). Compared to TGF-beta1-induced group, G-Rb1 and DPI depressed TGF-beta1-induced ROS production and p47phox overexpression. Meanhile, G-Rb1 and DPI decreased the levels of Col-I and FN.

CONCLUSION

G-Rb1 could inhibit TGF-beta1 induced ROS production and decrease the levels of Col-I and FN in a dose-dependent manner. The mechanism might be partly related to the suppression of p47phox expression.