RESUMEN
OBJECTIVES: Two new adjuvants from natural animal lipids (G2) and bacterial polysaccharide extracts (PC) were previously prepared by our group and showed a reduction in tracheal responsiveness. The aim of this study was to evaluate the preventive effect of recently introduced natural products (G2 and PC) on the development of asthma. MATERIALS AND METHODS: Asthma was induced using a standard method in four groups of BALB/c mice. A non-sensitized control group was also included in order to be compared with treated groups. Three groups were premedicated with novel agents named G2, PC, and a combination of these two for 20 days before starting the induction of asthma. Bronchoalveolar lavage fluid (BALF) was collected and analyzed for inflammatory cells. Interferon-γ, and IL-4 and the histopathological of both lungs were also evaluated. RESULTS: In all pretreated groups, the inflammatory cells infiltration especially eosinophils and smooth muscle hyperplasia decreased significantly. BALF cytology also showed significant decrease in eosinophil count in all pretreated groups. There was a significant increase in the BALF and serum INF-γ in all pretreated groups but the combination of G2/PC was more effective. BALF IL-4 decreased significantly in the group pretreated with a combination of G2 and G2/PC (4.11±0.86 and 4.02±0.52 pg/ml in G2 and G2/PC, respectively). Serum IL-4 in the PC group was significantly higher than the sensitized control. CONCLUSION: G2 and PC may effectively prevent asthma development by activation of the type 1 T helper system.