The protective effect of berberine hydrochloride on LPS‑induced osteoclastogenesis through inhibiting TRAF6‑Ca2+‑calcineurin‑NFATcl signaling pathway.

The present study investigated the protective effect of berberine hydrochloride on lipopolysaccharide (LPS) ‑induced acute bone destruction through inhibition of the TNF receptor associated factor 6 (TRAF6)‑Ca2+‑calcineurin‑nuclear factor of activated T‑cell 1 (NFATc1) signaling pathway. An osteoclast culture system of RAW264.7 cells induced by LPS in vitro was established. A polymerase chain reaction (PCR) assay was applied to determine the effect of berberine hydrochloride on the mRNA expression levels of fos‑related antigen 2 (Fra‑2), tartrate‑resistant acid phosphatase (TRAP), β3‑integrin, cathepsin K, dendritic cell‑specific transmembrane protein (DC‑STAMP), V‑type proton ATPase subunit d 2 (Atp6v0d2) and NFATcl. An ELISA assay was performed to measure the release of tumor necrosis factor‑α (TNF‑α). Western blot analysis was used to measure the effect of berberine hydrochloride on the expression of calcineurin in the LPS‑induced NFATc1 signaling pathway, as well as the expression levels of phosphoinositide phospholipase C‑γl (PLC‑γ1), toll like receptor 4 (TLR4) and TRAF6. The effect of berberine hydrochloride on Ca2+ concentration was detected using a confocal technique with a Flou‑3/acetoxymethyl ester Ca2+ probe. The PCR results demonstrated that berberine hydrochloride inhibited the mRNA expression levels of Fra‑2, TRAP, β3‑integrin, cathepsin K, DC‑STAMP, Atp6v0d2 and NFATc1. Furthermore, the ELISA results demonstrated that TNF‑α expression was decreased. The western blot analysis revelead that berberine hydrochloride treatment results in decreased expression levels of PLC‑γ1, TLR4 and TRAF6, and inhibition of Ca2+ influx. In conclusion, the results of the present study suggest that berberine hydrochloride targets TRAF6 and NFATc1, thus inhibiting osteoclastogenesis and bone destruction via inhibition of the TRAF6‑Ca2+‑calcineurin‑NFATcl signaling pathway.