Lentivirus-mediated TNF-α gene silencing and overexpression of osteoprotegerin inhibit titanium particle-induced inflammatory response and osteoclastogenesis in vitro.

Macrophages and osteoclasts release proinflammatory factors and promote osteoclastogenesis following the phagocytosis of wear particles. During this pathological process, receptor of nuclear factor κB ligand (RANKL) and tumor necrosis factor (TNF)-α are critical factors contributing to resorption and the inflammatory response. The present study aimed to construct recombination lentivirus vectors carrying TNF-α small interfering (si)RNA and osteoprotegerin (OPG) cDNA, and to examine the effects of Lenti‑siTNFα‑OPG on the wear particle‑induced inflammatory response and osteoclastogenesis in a titanium (Ti) particle‑induced‑inflammatory response cell model. Lenti‑siTNFα‑OPG vectors were constructed and transnfected into RAW264.7 and MC3T3‑E1 cells, respectively, prior to particle stimulation. The protein levels of TNF‑α, OPG and RANKL were evaluated using western blot analysis and enzyme‑linked immunosorbent assays, and the mRNA expression levels of the inflammatory factors, TNF‑α, interleukin (IL)‑1β and IL‑6, as well as OPG and RANKL, were measured using reverse transcription‑quantitative polymerase chain reaction analysis. The activity of alkaline phosphatase (ALP) was examined using an ALP kit. In the presence of the Lenti‑siTNFα‑OPG vector, the mRNA expression levels of the inflammatory factors and RANKL were downregulated, as were the protein levels of TNF‑α. The mRNA expression and protein levels of OPG were upregulated, and ALP activity was increased. These findings suggested that Lenti‑siTNFα‑OPG transfection inhibited the wear particle‑induced inflammatory response and osteoclastogenesis, which warrants further investigation for the prevention and/or treatment of wear particle-induced osteolysis.