Expression Of TNF-α, MMP-9 And VEGF In BALF Of Rats With Emphysema And Their Mutual Relationship

Objective:To investigate the expression of tumor necrosis factor alpha(TNF-α),matrix metalloproteinases-9(MMP-9) and vascular endothelial growth factor(VEGF) in bronchoalveolar lavage fluid(BALF) of rats with emphysema and their mutual relationship,and the effect of infliximab on them.Methods:Thirty-nine rats were randomly divided into a normal control group,an emphysema group,an infliximab-intervention group.Rat models of emphysema were established by exposure to cigarette smoking daily for 74 days.The intervention group was treated with infliximab,and the normal control group and the emphysema group were injected with normal saline 0.2ml.The levels of TNF-α,MMP-9 and VEGF in BALF were measured with ELISA.Lung tissue section stained by hematoxylin and eosin(HE) was observed to study the morphological alternations.Mean liner intercept(MLI) and mean alveolar numbers(MAN) were measured.Results:MLI in the emphysema group rats[(97.52±23.75)x10-6m] was higher than that in the normal control[(41.26±4.50)x10-6m] and the intervention group[(57.69±7.37) x10-6m](all P<0.05) while MAN was decreased on the contrary(p<0.05), compared with the normal control and the infliximab-intervention group.The levels of TNF-a and MMP-9 in BALF were higher in the emphysema group rats[(60.51±4.01)pg/ml],(6.89±1.61)ng/ml] than in the normal control[(36.02±3.65)pg/ml,(2.94±0.62)ng/ml] and the intervention group [(41.47±5.31) pg/ml], (4.52±0.69)ng/ml](all P<0.05) while the levels of VEGF [(2.63±0.63)ng/ml] was decreased on the contrary(P<0.05),compared with the normal control[(5.30±1.07)ng/ml], but no significant differences were found between the levels in the emphysema group and The intervention group(p>0.05).Positive correlations were demonstrated between the levels of TNF-a and MMP-9 in BALF in the emphysema group(r=0.67, P<0.05),but no significant correlations were found between the levels of TNF-α,MMP-9 and VEGF(r=-0.23,-0.012 respectively,all P>0.05).Conclusion:Enhancement of TNF-α, MMP-9 and weakness of VEGF in expression all can promote development of emphysema of smoking rats.Infliximab may inhibit the formation of airway inflammation in rats with emphysema,so there is certain clinical significance in the treatment of the disease.Expressions of TNF-α,and MMP-9 reveal no significant correlations with VEGF,so weakness of VEGF in expression and elevated levels of the two cytokines may promote the development of emphysema in different ways.