Objective: To investigate the effect and mechanism of tripterine on airway inflammation in asthmatic mice.
Methods: 30 BALB/c mice were randomly divided into a control group, an asthmatic group (ovalbumin-sensitized) and a tripterine (1 mg/kg, introperitoneally)-treated group. Pathologic changes in lung tissues, number of eosinophils in bronchoalveolar lavage fluid (BALF) and expression of stem cell factor (SCF) protein in lung were observed. In vitro, we established coculture system of bone marrow derived-mast cells from C57B6 mice and fibroblast NIH3T3, which were then treated by 2 micro mol/L of tripterine, and compared with NIH3T3 and mast cells. Concentration of histamine and eotaxin in supernants of coculture was measured by fluorometry and ELISA respectively, and expression of SCF protein in fibroblasts from cocultures was analyzed with immunohistochemistry.
Results: Compared with the asthmatic group, less inflammatory cell infiltration in lung tissues was observed in the tripterine-treated group. There was significant difference in the number of eosinophils in BALF between the tripterine-treated group [(0.56 +/- 0.03) x 10(6)/L] and the asthmatic group [(1.25 +/- 0.40) x 10(6)/L, P < 0.05]. So was the expression of SCF protein in lung tissue [0.74 +/- 0.20, 2.50 +/- 0.19, P < 0.01]. In vitro, the concentration of histamine and eotaxin in coculture supernants and the expression of SCF protein in fibroblasts from coculture were (3.83 +/- 0.41) ng/ml, (5.79 +/- 0.40) ng/ml and (95 +/- 3)%, respectively; after tripterine intervention, the data changed to (2.88 +/- 0.35) ng/ml, (4.24 +/- 0.29) ng/ml, (17 +/- 5)% (all P < 0.01).
Conclusions: Tripterine might suppress airway inflammation in asthmatic mice, probably by downregulating the expression of SCF in fibroblasts, then inhibiting the production of histamine and eotaxin in mast cells.