Wear particle-mediated expressions of pro-inflammatory cytokines, NF-κB and RANK were impacted by lanthanum chloride in RAW264.7 cells

To explore the impact of different concentrations of lanthanum chloride (LaCl3) on critical components of wear particle-mediated signaling pathways in inflammation and osteoclastogenesis, RAW264.7 cells were naturally divided into eight groups and analyzed by CCK-8 assay, flow cytometry, ELISA, RT-PCR and western blot after treatments. The results showed that three concentrations of LaCl3 had no influence on viability of RAW264.7 cells and down-regulated receptor activator of nuclear factor κB (RANK) instead of macrophage colony-stimulating factor receptor (M-CSFR). Additionally, 2.5 and 10 μmol/L LaCl3 could significantly inhibit gene and protein levels of pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β, i.e., TNF-α and IL-1β and NF-κB/p65, but 100 μmol/L LaCl3 did not exert an obvious inflammation-inhibiting effect, and even induced inflammation. In conclusion, these findings demonstrated that LaCl3 was able to suppress wear particle-induced inflammation and activation of NF-κB in a certain range of concentrations in vitro and mainly decrease the expression of RANK, but not M-CSFR, all of which were generally recognized to play a pivotal role in osteoclastogenesis.

Graphical AbstractAgarose gel electrophoresis results of PCR products (Wear particles could up-regulate five target gene expression levels, and the levels were decreased by LaCl3 except M-CSFR; the effects of LaCl3 on TNF-α, IL-1β and NFATc1 mRNA levels were concentration-dependent. A: blank control group; B: wear particle group; C1: wear particle+2.5 μmol/L LaCl3 group; C2: wear particle+10 μmol/L LaCl3 group; C3: wear particle+100 μmol/L LaCl3 group; D1: 2.5 μmol/L LaCl3 group; D2: 10 μmol/L LaCl3 group; D3: 100 μmol/L LaCl3 group)Figure optionsDownload full-size imageDownload as PowerPoint slide