Regulatory effects of L-arginine on interleukin-6 and interleukin-8 in airway epithelial cell line

AIM To investigate the effects of L-arginine(Arg)on the production of interleukin-6(IL-6)and interleukin-8(IL-8)in NCI-H292 cells.METHODS NCI-H292 cells were divided into MEM group,MEM + A group(MEM + Arg),RPMI group(RPMI1640 medium containing 1 mmol·L-1 Arg),regular medium group(Arg 1 mmol·L-1)and dexamethasone group(MEM + 10 μg·L-1 dexamethasone).NCI-H292 cells were stimulated with tumor necrosis factor(TNF-α)or lipopolysaccharide(LPS),and the production of IL-6 and IL-8 induced by different concentrations of TNF-α or LPS in each groups were observed.The expressions of IL-6 and IL-8 were determined by ELISA,and the levels of mRNA were detected by dot blotting.RESULTS There was positive correlation between TNF-α and IL-6(r = 0.644,P 0.01),IL-8(r = 0.715,P 0.01),respectively.With or without LPS or TNF-α stimulation,the levels of IL-6 and IL-8 in the MEM group were much higher than those in the MEM + A group,RPMI group and dexamethasone group(P 0.01).The level of IL-6 in the MEM group was higher than that in the regular medium group(P 0.01).The level of IL-8 in the MEM group was higher than that in the regular medium group(P 0.01)with TNF-α stimulation,but no significance difference when stimulated by LPS(P 0.05).There were no significant differences in IL-6 and IL-8 between the MEM + A group and dexamethasone group(P 0.05).At 4,8 and 24 h of incubation,the mRNA expressions of IL-6 and IL-8 in the MEM + A group were lower than those in the MEM group(P 0.05).CONCLUSION A certain concentration of Arg can inhibit the release of IL-6 and IL-8 in NCI-H292 cells by decreasing the transcriptional activity of IL-6 and IL-8.