Effect Of Dexamethasone On Basic Fibroblast Growth Factor And Nerve Growth Factor In The Airway Remodeling Of Asthma

Objective To investigate the expression of basic fibroblast growth factor(bFGF) and nerve growth factor(NGF) in airway remodeling rat models of asthma, and to study the relationship among the expression of bFGF,NGF and the airway remodeling. The effects of dexamethasone on them were also observed.Methods Forty wistar rats were randomly divided into four groups, which are early-intervention group(E group), late-intervention group(L group), non-intervention group(N group) and control group(C group).Each rat which was in E group, N group, L group used intra-peritoneal injection twice with 10% ovalbumin(OVA) antigen suspension and ultrasonic atomizing inhalation with 1% ovalbumin(OVA) eight weeks to sensitize and stimulate asthma, to establish the model of airway remodeling in asthma. Begin from the first day of ultrasonic atomizing inhalation with OVA, each rat in the E group were used intra-peritoneal injection with the dexamethasone(0.5mg/kg) one hour before ultrasonic atomizing inhalation, and begin from the fifteenth day of ultrasonic atomizing inhalation with OVA, the L group used intra-peritoneal injection with the dexamethasone(0.5mg/kg) one hour before ultrasonic atomizing inhalation, while C group used sodium chloride to instead of OVA and dexamethasone. Lung tissues were sliced and stained with hematoxylin and eosin. The levels of NGF in lung tissues were measured by immunohistochemistry method. The expression of bFGF in blood serum were measured by ELISA method. The airway morphological parameters were measured by computer image analysis software. The data were analyzed by SPSS16.0.Results The various remodeling in airway were observed at all of the rats in E group, L group and N group. The thicknesses of bronchus wall and airway smooth muscle in E group were significantly thinner than that in L group and N group (P<0.05), the expression of bFGF in blood serum in E group were lower than that of L group and N group (P<0.01), the levels of NGF in lung tissues in E group were also lower than that of L group and N group (P<0.01), and the expression of both bFGF and NGF were related with the thickness of bronchus wall and the thickness of airway smooth muscle in asthmatic rats(P<0.001).Conclusions Early treatment with dexamethasone could partly reverse the airway remodeling of asthma, and inhibiting the expressions of bFGF and NGF may be the one of the mechanisms. The expression of both bFGF and NGF were related with the thickness of bronchus wall and the thickness of airway smooth muscle in asthmatic rats, and the bFGF and NGF may play an important role in airway remodeling of asthma, suggested that they might become one of markers to evaluate the extent of airway remodeling.