Role Of The Adiponectin Binding Protein, T-cadherin,in Emphysema Induced By Cigarette Smoke Exposure In Rat

Objective:To explore the role of adiponectin binding protein, T-cadherin, in emphysema induced by cigarette smoke exposure in rat, on the one hand,we observed the expression levels of T-cadherin in bronchial epithelial and pulmonary vascular endothelial cells, as well as serum adiponectin level. On the other hand, we observed either T-cadherin or adiponectin had correlation with emphysema.Methods:Sixteen 6-week healthy male rats [weight(190±10) g ]were randomly divided into cigarette smoke-exposed group and control group. Each group with eight rats, which raised for 6 months. Emphysema was assessed by measuring the mean alveoli number(MAN),mean linear intercept(MLI). Levels of adiponectin were assayed in serum using an ELISA(R&D Systems). The expression levels of T-cadherin in bronchial epithelial and pulmonary vascular endothelial cells were qualitavively analyzed by immunohistochemical analysis,which were semi-quantitatively assayed by Image-Pro Plus version 6.0 software.Results:1.The MAN was lower in cigarette smoke-exposed group(163.72 ± 31.04) than control group(203.66±8.51), while the MLI was higher in cigarette smoke-exposed group[(76.33±10.98)μm] than control group[(65.57±5.72)μm]. The differences were all significant(P<0.05), and MAN was negatively correlated with MLI(r=﹣0.791,P<0.01).2.Cigarette smoke-exposed group[(8.14±1.17)μg/ml] had higher level of serum adiponectin compared with control group[( 6.57 ± 1.15) μg/ml]. The difference was significant(P<0.05). Serum adiponectin level was negatively correlated with MAN, while it was positively with MLI(r = ﹣0.673, 0.751; P<0.05).3.Cigarette smoke-exposed group [( 30.79 ± 1.22) × 10-4] had lower level of T-cadherin in pulmonary vascular endothelial cell compared with control group[(47.32±3.42)×10-4]. The difference was significant(P<0.05). T-cadherin level in pulmonary vascular endothelial cell was positively correlated with MAN, while it was negatively with MLI(r = 0.674, ﹣0.615; P<0.05).4.The levels of T-cadherin in bronchial epithelial cell was no significantly difference between cigarette smoke-exposed group [(308.01±16.82)×10-4] and control group[(293.14±19.60)×10-4]. The levels of T-cadherin in bronchial epithelial cell were no correlation with MAN and MLI.5.Serum adiponectin level was negatively correlated with level of T-cadherin in pulmonary vascular endothelial cell(r=﹣0.677,P<0.05), while it had no correlation with level of T-cadherin in bronchial endothelial cell.Conclusions:Cigarette smoke-exposed could reduce the expression of T-cadherin in pulmonary vascular endothelial cell. It weakened the protective effect on vascular endothelial and elevated serum adiponectin level., then both could promote the formation of emphysema.