Matrix metalloproteinase (MMP)-13 has a degradation effect on type II collagen and is expressed in osteoblastic cells and hypertrophic chondrocytes. However, the role of MMP-13 is not completely understood. This study investigated the effect of exogenous Hyaluronic acid (HA) on the expression of MMP-13 in the healing process of bone defects.

After making a bone defect in the metaphysis of the distal femur in rats, HA was instilled into the defect in the experimental group. In the control group, a bone defect was made but HA was not instilled. Two weeks after the experiment, the rats were sacrificed and the callus that filled the bone defects was obtained. A histological examination and real time reverse transcription polymeric chain reaction (RT-PCR) were performed to investigate the healing response and expression of MMP-13.

Histologically, the proliferation of osteoblasts and the formation of osteoid were more active in the experimental group. Nevertheless, the level of MMP-13 expression was significantly lower in the experimental group than in the control group.

From the results of this study, it appears that exogenous HA inhibits the expression of MMP-13 at the early stage of bone healing.