Effect and influence of mitogen-activated protein kinases pathway on airway inflammation and epithefium apoptosis in asthmatic guinea pigs

Abstract

Objective To study the airway inflammation, epithefium apoptosis, p38 MAPK expression level in asthmatic guinea pigs and the effect of dexmethasone therapy. Methods Forty-eight guinea pigs were randomly divided into 4 groups: control group, asthma group, dexmethasone-treated group and MAPK pathway inhibitor SB203580 trea-ted group, 12 guinea pigs in each group.Hematoxylin and eosin staining, Massong Trichrome stain, Periodic Acid Schifgtaining were performed.Histological changes were detected under the optical or the electron microscope.Immunohistochemistry assays were used to determine the status of IL-5 and phosphorylated p38 MAPK in airway epitheliam.Inflammatory factor level was detected by enzyme linked immunosorbent assay(ELISA). Immunohistochemistry assays of cleaved caspase 3 was used to detect the level of epithefium apoptosis. Results Compared with the control group, guinea pigs in the asthmatic group showed significantly higher airway epithelium apoptosis(detected as the cleaved caspase-3 imumunoreactive cells), lung tissue phosphorylated p38 MAPK expression level, IL-5 level in BALF(P 0.05). Compared with SB203580 group, guinea pigs in the DEX group showed significantly lower airway epithelium apoptosis, lung tissue phosphorylated p38 MAPK expression level, and IL-5 level in BALF(P<0.01). Conclusions Airway inflammation is involved in epithefium apoptosis in the asthmatic guinea pigs.The interfering effect of apoptosis by DEX may be partly related to inhibition of lung tissue phosphorylated p38 MAPK expression level, and p38 MAPK may participate in the asthmatic inflammation and induce airway epithelium apoptosis. Key words: Bronchial asthma; Apoptosis; Inflammation; Mitogen-activated protein kinase; Dexmethasone; Interleukin