Effects of long-term smoking on expression of IL-8 and E-selectin in rat lungs

Objective To investigate the influence of long-term smoking on the expression of inflammatory factors in rat lung tissue. Methods Fifty-six male SD rats were randomly divided into four groups:control,low-,moderate-,and highdose group.The rats in each group were exposed to cigarette smoke at different dose for 12 weeks.The level of interleukin-8 (IL-8)in bronchoalveolar lavage fluid(BALF)was measured with radioimmunoassay.Immunohistochemistry assay was carried out to examine the expression of E-selectin in lung tissue. Results The levels of IL-8 in BALF increased significantly in high-,moderate-,and low-dose group(0.77±0.010,0.71±0.171,and 0.62±0.088,respectively)compared to that of the control group(0.28±0.133,P<0.01).The expression of E-selectin in pulmonary vascular increased significantly in high-,moderate-,and low-dose group(0.27±0.030,0.18±0.034,and 0.16±0.025,respectively)compared to that of the control group(0.07±0.023,P<0.01).The level of IL-8 in BALF was positively correlated with the expression of E-selectin in moderate-dose group(r=0.716,P<0.01). Conclusion Long-term smoking can result in high expressions of IL-8 and E-selectin in airw ay and induce airw ay inflammation and cause serious damage in bronchial lung tissue in rats.