Effects of Tim‑3 silencing on the viability of fibroblast‑like synoviocytes and lipopolysaccharide‑induced inflammatory reactions

The objective of the present study was to investigate the effects of Tim‑3 silencing on cell viability and lipopolysaccharide (LPS)‑induced inflammatory reactions in fibroblast‑like synoviocytes (FLS). T‑cell immunoglobulin mucin domain molecule (Tim)‑3 expression in FLS obtained from patients with rheumatoid arthritis (RA) and normal controls were detected by western blot analysis and reverse transcription‑polymerase chain reaction (RT‑PCR). Small interfering (si)RNA was transfected using Lipofectamine® 2000 to decrease Tim‑3 expression. Following transfection, FLS were stimulated by LPS. An MTT assay, RT‑PCR and western blot analysis were performed to measure cell viability, Toll‑like receptor 4 (TLR4) signaling pathway‑related protein expression and inflammatory cytokine release, respectively. The results of the present study indicated that Tim‑3 expression was increased in FLS from patients with RA compared with FLS from healthy controls. Transfection of Tim‑3 siRNA significantly decreased Tim‑3 expression in FLS from patients with RA. Notably, Tim‑3 silencing decreased FLS cell viability. Following stimulation with LPS, cell viability and the expression of TLR4, myeloid differentiation protein gene 88 (MyD88) and nuclear factor‑κB (NF‑κB) p65 were enhanced in FLS. By contrast, Tim‑3 silencing attenuated LPS‑induced cell proliferation and the expression of TLR4, MyD88 and NF‑κB p65. In addition, LPS significantly increased levels of cytokines in the supernatant, including tumor necrosis factor‑α, interferon‑γ and interleukin‑6 (P<0.01). By contrast, Tim‑3 silencing significantly decreased LPS‑induced cytokine release (P<0.01). However, Tim‑3 silencing did not affect TLR4, MyD88 and NF‑κB p65 expression and the release of cytokines in cells that did not undergo treatment with LPS. Therefore, the results of the present study indicate that Tim‑3 silencing decreases the viability of FLS in RA and attenuates the LPS‑induced inflammatory reaction.