H19 promotes the proliferation of osteocytes by inhibiting p53 during fracture healing.

OBJECTIVE

We explored the possible mechanism underlying the expression change of H19 during fracture healing.

MATERIALS AND METHODS

A total of 18 male SD mice aged from 6-8 weeks old (18.5-24.6 g) were selected to establish tibial fracture models. The left tibia undergoing sham surgery was considered as the control group, and the right tibia undergoing sawing treatment was considered as the experimental group. The control tibia and fracture tibia from three mice were harvested at six time points after operation, respectively. QRT-PCR was utilized to detect the changes of H19 and p53 mRNA expression.

RESULTS

Compared with the control group, the expression of H19 in the experimental group was significantly increased at 4, 8, and 12 d. However, there was no significant difference in the expression of H19 between the experimental group and the control group at 16, 20, and 24 d. The proliferation of chondrocytes and osteoblasts from mouse and human was significantly inhibited, and the apoptosis was significantly increased after interference of H19. As p19 plays important roles in diverse biological process, we detected the expression level of p19 after inference of H19. In addition, knockdown of H19 significantly up-regulated the expression of p53 in osteoblast cell lines, while the down-regulation of p53 expression reversed the proliferation of osteoblasts.

CONCLUSIONS

H19, as a molecular marker for promoting fracture healing, promote the proliferation of osteocytes by inhibiting the expression of p53.