Objective: To investigate the effects of osthole on proliferation of neonatal rat osteoblast and the mechanism.
Methods: Ten 24 hours old SD rats were executed by dislocating. The cranium of rats were removed and cut into blocks of 1 mm x 1 mm size. After digested by trypsin for 15 min, the cranium were digested by type I collagenase for one hour two times. The mixed cells were cultured in thermostat incubator with 5% CO2 under the condition of 37 degrees C. To identify the cells, ALP staining and alizarin red staining were performed after cultured 48 h and 28 d. The osteoblasts were randomly divided into five groups. Cells were treated with osthole at concentrations of 100, 50, 25, 12.5, 0 micromol/L. CCK-8 method was used to evaluate the proliferation after 24 h,48 h and 72 h. The expression of PCNA and beta-catenin protein were detected through the method of Western Blot after one week.
Results: The cells had irregular shapes and showed typical features of osteoblast. The results of ALP staining and alizarin red staining were both positive. CCK-8 detection showed that the osthole with final concentration of 100 micromol/L inhibited the proliferation of osteoblast after 24 h, while the osthole with final concentrations of 50 micromol/L and 25 micromol/L displayed the inhibition effect after 48 h. The osthole of 12.5 micromol/L had no obvious influence on the proliferation of osteoblast. The result of Western Blot showed that osthole reduced the expression of PCNA and beta-catenin protein in a dose-dependent manner.
Conclusion: The osthole with final concentrations of 100, 50, 25 micromol/L inhibited the proliferation of osteoblast (P < 0.05). The osthole with final concentrations of 12.5 micromol/L had no obvious influence on the proliferation of osteoblast (P > 0.05). These findings demonstrate that osthole may inhibit the proliferation of osteoblast by regulating the Wnt/beta-catenin signaling in osteoblast.