The effect of procyanidin on periprosthetic osteolysis caused by TCP wear particles in the mouse calvaria and its mechanism

Abstract

To investigate the protective effects of procyanidin on periprosthetic osteolysis caused by tricalcium phosphate (TCP) wear particles in the mouse calvaria and its mechanism. Forty-eight male ICR mice were randomly divided into sham group, TCP group, and procyanidin (0.2 mg/kg, 1 mg/kg, 5 mg/kg)-treated group (n=12). A periprosthetic osteolysis model in the mouse calvaria was established by implanting 30 mg of TCP wear particles onto the surface of bilateral parietal bones following removal of the periosteum. On the 2nd day post-operation, procyanidin (1 mg/kg, 5 mg/kg) was locally injected to the calvaria under the periosteum every other day. After 2 weeks, all the mice were sacrificed to collect the blood samples and the calvaria. Periprosthetic osteolysis and osteoclastogenesis in the mouse calvaria were observed by tartrate resistant acid phosphatase (TRAP) staining and HE staining. mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 in the periprosthestic bone tissue were examined by real-time fluorescence quantitative PCR. Serum contents of total anti-oxidation capacity (T-AOC) and MDA, and superoxide dismutase (SOD) activity were determined by chemical colorimetry. Protein expressions of autophagic biomarkers such as Beclin-1 and LC-3 in periprosthetic bone tissue of the calvaria were examined by Western blot. Compared with sham group, periprosthetic osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1, and serum MDA content were increased significantly in the TCP group (P＜0.05), whereas serum T-AOC level and SOD activity were decreased. The protein expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were both up-regulated markedly in the mouse calvaria of TCP group (P＜0.05). Compared with TCP group, osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 and serum MDA content were decreased obviously in the procyanidine group (P＜0.05), serum T-AOC level and SOD activity were increased, the expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were down-regulated obviously in the mouse calvaria of procyanidin group (P＜0.05). Procyanidin has a protective effect of periprosthetic osteolysis caused by TCP wear particles in the mouse calvaia, its mechanism may be mediated by inhibition of oxidative stress and autophagy.