Mechanism by which gypenosides alleviate oxidative stress injury induced by h2o2 in rat osteoblasts / 中国组织工程研究

ABSTRACT

BACKGROUND: Gypenosides have antioxidant properties, with beneficial effects such as reducing blood pressure, anti-aging and anti-tumor, but the specific protective mechanism is not clear. It is also unknown whether gypenosides have effect on the proliferation and differentiation of oxidative stress-damaged osteoblasts. OBJECTIVE: To investigate the mechanism by which gypenosides alleviate oxidative stress injury in rat osteoblasts and the effect on the proliferation and differentiation of oxidatively damaged osteoblasts. METHODS: Monolayer cell culture method was used to separate neonatal rat skull cells for the culture of osteoblasts. In this experiment, there were three groups, with normal culture medium as blank group, normal culture medium+oxidative damage as control group, and normal culture medium containing gypenosides and oxidative damage as experimental group. Osteoblasts in the experimental and control groups were cultured in the culture medium containing 150 μmol/L H2O2. After 3 and 5 days of intervention, cell counting kit-8 method was used to detect the effects of gypenosides on oxidative damage of osteoblasts. Alkaline phosphatase staining was used to detect alkaline phosphatase activity on day 7 after induction. Alizarin red staining was used on day 21 of induction to observe osteoblast mineralization. Western blot was used to detect the expression of NOX4, bone morphogenetic protein 2 and Smad4. The experimental protocol was approved by the Animal Ethics Committee of Guangzhou University of Chinese Medicine. RESULTS AND CONCLUSION: Gypenosides could promote the proliferation of oxidatively damaged osteoblasts. The results of alkaline phosphatase staining and alizarin red staining showed that gypenosides could promote the differentiation of oxidatively damaged osteoblasts. Compared with the control group, gypenosides could downregulate the expression of NOX4 protein and upregulate the expression of bone morphogenetic protein 2 and Smad4 protein in the experimental group, with statistically significant results (P < 0.05). All these findings indicate that gypenosides have a protective effect on H2O2-induced oxidative stress injury in osteoblasts, and promote the proliferation and differentiation of damaged osteoblasts. The mechanism may be related to the inhibition of Nox4 protein expression and the activation of bone morphogenetic protein/Smad pathway.