| Objective To investigate the effect of glucocorticoids on matrix metalloproteinase-9(MMP-9) and endothelin-1(ET-1) on airway remodeling of asthma in wistar rats and clinical value of glucocorticoids improving airway remodeling in wistar rats with asthma.Methods An animal model of asthma was established by ovalbumin(OVA) sensitizing challenge to 40 wistar rats. The rats were devided into normal control group(group C), modelling group(group N), early intervention group(group E), and late intervention group(group L).The rats of group N,group E,group L were established by intra-peritoneal injection of ovalbumin (100g/L) on the 1st and 8th day. after a week, the rats were challenged with aerosolized OVA(10g/L) for 20 mins per day. Aerosol inhalation lasted for 8 weeks. Dexamethasone was used by intraperitoneal injection 1 hour before inhaling OVA in group E and 2 weeks after inhaling OVA in group L.The rats of group C were given normal saline.The rats were killed in 24 hours after last sensitization. ET-1 contents in serum were detected by radioimmunoassay. Lung tissue were cut to be fixed,paraffin embedded,pathological section,HE staining and Masson staining immunohistochemistry staining. The morphological changes of airway were observed by pathological image analysis system.Results Smooth muscle and airway wall thickness and collagen area was thicker than control group, while was markedly thinner than that in the modelling group(group N) and late intervention group(group L)(P<0.01). Smooth muscle and airway wall thickness and collagen area in the late intervention group(group L) was thinner than that in the modelling group(group N)(P<0.01). The expression level of MMP-9 and ET-1 in the early intervention group(group E) was higher than that in the control group(group C), while was lower than that in the modelling group(group N) and late intervention group(group L)(p<0.05). The expression level of MMP-9 and ET-1 in the late intervention group(group L) was lower than that in the modelling group(group N)(p< 0.05).Conclusion In the airway remodeling of asthma,glucocorticoids affected the expression of MMP-9 and ET-1.It reduced extracellular matrix by decreasing collagen deposition and inhibited airway wall and smooth muscle proliferation.Glucocorticoids can only delay but not reverse airway remodeling if pathogenic factor still exist. |
