Polyphyllin I alleviates osteoblasts injuries induced by TCP wear particles in vitro via inhibition of autophagy / 中草药

ABSTRACT

Objective: To observe the effect of polyphyllin I (PPI) on osteoblasts injuries induced by tricalcium phosphate (TCP) wear particles in vitro, and explain its regulation mechanisms. Methods: Primary osteoblasts obtained from the calvaria of neonatal SD rat by the series of digestion were identified with ALP staining. The osteoblasts were treated with TCP wear particles (TCP, 0.1 mg/mL) for 48 h to establish an in vitro injuries model of the calvarial osteoblasts. The experiment was randomly divided into control group, model (TCP, 0.1 mg/mL) group, PPI (30 μg/mL) group and PPI (100 μg/mL) group. CCK-8 and chemical colorimetry were used to examine cell viability and lactic dehydrogenase (LDH) content in culture media; Real-time PCR was performed to detect mRNA levels of ALP, Collagen I and RUNX2 in osteoblasts; The flow cytometry was used to examine apoptosis of osteoblasts using Annexin V/PI double staining; When the osteoblasts were treated for 14 d, mineral nodules formation was observed with alizarin S staining; Western blot was applied to examine proteins expression of Bax, Bcl-2, cleaved Caspase-3, Atg5, p62, and microtubule associated protein 1 light chain3 (LC-3). Results: Compared with control group, model group showed that the cell viability of osteoblasts, mRNA levels of ALP, Collagen I and RUNX2, and mineral nodules formation were significantly decreased; LDH content, percentage of apoptosis and proteins expression of Bax, cleaved Caspase-3, Atg5, LC-3 and the ratio of LC-3II/LC-3I were obviously increased in calvarial osteoblasts, whereas proteins expression of Bcl-2 and p62 was remarkably decreased. Compared with model group, PPI groups indicated that cell viability of osteoblasts, mRNA levels of ALP, Collagen I and RUNX2, and mineral nodules formation were dramatically increased; LDH content, percentage of apoptosis, protein expressions of Bax, cleaved Caspase-3, Atg5, and LC-3 and the ratio of LC-3II/LC-3I were obviously decreased, but Bcl-2 and p62 expression were obviously increased. Conclusion: PPI alleviates osteoblasts injuries induced by TCP wear particles via inhibition of autophagy.