Effect of nicotine on the inflammatory response of chondrocytes induced by interleukin-1β and nuclear factor kappa B the signal pathway

Abstract

Objective To explore effect of nicotine on the inflammatory response of chondrocytes induced by interleukin-1β (IL-1β) and nuclear factor kappa B (NF-κB) signal pathway. Methods Rat primary chondrocytes were isolated by collagenase digestion. Effect of 10-8, 10-7, 10-6, 10-5 mol/L nicotine on chondrocytes viability was detected by methyl thiazol tetrazolium (MTT). Chondrocytes were divided into 5 groups, normal group (without any drug stimulation), model group (10 μmol/L IL-1β), nicotine low, middle and high dose group (10-8, 10-7, 10-6 mol/L+ 10 μmol/L IL-1β). The viability of chondrocytes was detected by MTT assay. The content of tumor necrosis factor alpha (TNF-α), interleukin gamma (IFN-γ) and IL-6 was detected by enzyme linked immunosorbent assay (ELISA). The expression of nitric oxide was detected (iNOS), p-NF-κB p65 and p-IκBα was detected by Western blotting. Results Compared with normal group, 10-8, 10-7, 10-6 mol/L nicotine [(0.52±0.05), (0.64±0.06), (0.78±0.07)] increased chondrocytes’ viability (P=0.032, 0.004, 0.000). Compared with normal group, cell viability was decreased(P=0.000), the level of TNF-α, IFN-γ and IL-6 was increased [(8.73±0.84), (17.24±1.76), (2.78±0.21) ng/L] (P=0.002, 0.001, 0.001), the expression of iNOS, p-NF-κB p65 and p-IκBα was up-regulated in model group(P=0.003, 0.000, 0.000). Compared with model group, cell viability was decreased, (P=0.009, 0.000, 0.000) the level of TNF-α, IFN-γ and IL-6 was reduced [(6.61±0.14), (15.36±1.33), (2.29±0.19) ng/L, P=0.004, 0.000, 0.000; (5.52±0.50), (13.23±1.27), (1.82±0.17) ng/L, P=0.007, 0.000, 0.000; (3.93±0.40), (10.45±1.04), (1.54±0.15) ng/L, P=0.005, 0.000, 0.000], the expression of p-IκBα(P=0.009, 0.001, 0.000) was down-regulated in nicotine low, middle and high dose group, the expression of iNOS and p-NF-κB p65 was down-regulated in middle and high dose group (0.38±0.04, 0.40±0.04, P=0.008, 0.000; 0.31±0.30, 0.30±0.05, P=0.000, 0.000). Conclusion These results suggested nicotine could inhibit inflammatory response of chondrocytes induced by IL-1β via inhibition of NF-κB signal pathway. Key words: Nicotine; Interleukin-1β; Chondrocytes; Inflammatory; Nuclear factor kappa B signal pathway