Background Epidemiologic studies have shown that alcohol plays a pivotal role in the development of osteonecrosis of the femoral head (ONFH). However, few studies have discussed the pathogenesis of or interventions for alcohol-induced ONFH.

Objectives The aim of this study was to explore the underlying mechanism of alcohol-induced ONFH and the protective effect of pifithrin-α (PFTα).

Results Through a series of in vitro assessments, we found that ethanol treatment significantly activated p53, suppressed Wnt/β-catenin signaling and inhibited osteogenic-related proteins, including runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), osteopontin (OPN) and collagen I (COL1). Furthermore, by separating the cytoplasmic and nuclear proteins, we found that ethanol inhibited osteogenesisby impairing the accumulation of β-cateninin both the cytoplasm and nucleus in human bone mesenchymal stem cells (hBMSCs), which resulted from activating glycogen synthase kinase-3β (GSK-3β). In this in vivo study, we established alcohol-induced ONFH in rats and investigated the protective effect of PFTα. Micro-CT, hematoxylin & eosin (H&E) staining, immunohistochemical analyses, immunofluorescence staining, TUNEL staining, and fluorochrome labeling were performed to reveal the PFTα-induced therapeutic effects. H&E findings combined with TUNEL, caspase-3-cleaved immunohistochemical staining, and micro-CT images revealed obvious ONFH in the alcohol-administered rats, whereas significantly less osteonecrosis developed in the rats injected with PFTα. As the initiator of osteogenesis, RUNX2 and its downstream targets OCN, OPN, COL1 were immunostained in the femoral heads. These results indicated that those osteogenic-related proteins were significantly decreased in the alcohol-administered rats, whereas these results were reversed in the PFTα-injected rats. Fluorochrome labeling showed a similar result in that alcohol significantly reduced the osteogenic activity in the rat femoral head, which was blocked by the injection of PFTα.

Conclusions Pifithrin-α, a p53 inhibitor, was able to block the ethanol-triggered activation of p53 in hBMSCs and alcohol-induced ONFH in a rat model. Its antagonistic effect against ethanol's effect on hBMSCs could be a clinical strategy to prevent the development of alcohol-induced ONFH.

Acknowledgements The current study was supported by grants from the National Natural Science Foundation of China (no. 81272003 andno. 81301572) and the SMC-Chen Xing Plan for Splendid Young Investigators of Shanghai Jiao Tong University.

Disclosure of Interest None declared