ACTIVITY OF THE POLYSACCHARIDE CHITOSAN ON THE EPITHELIAL LINING AFTER ORAL ADMINISTRATION.

CANALI, MAGDALENA; PORPORATTO, CARINA; CORREA, SILVIA G.

Córdoba

Congreso; VII Congreso Latinoamericano de Inmunología; 2005

Asociación Latinoamericana de Inmunología

Intestinal epithelial cells (IEC) are key components of the mucosal immune system acting as lining barrier, sensing luminal antigens or sampling macromolecules. Chitosan is a mucoadhesive polysaccharide able to increase the intestinal permeability, to deliver antigens and to adjuvate mucosal vaccines. To evaluate the effect of chitosan on IEC, rats received 200 µl of diluent (acetic acid) or 1, 3 or 5 mg of chitosan and 16 h later we removed the small gut and we purified IEC by incubating the tissue in 1 mM dithiothreitol, 30 mM EDTA followed by shaking in calcium and magnesium-free RPMI. The mean fluorescence intensity of CD54 expression and  the percentage of pSTAT-3 positive IEC (flow cytometry) were unaffected by the administration of chitosan. The NO/arginase balance (colorimetric method) showed an increment in the arginase pathway in a dose dependent manner: 10.49 (diluent), 14.68 (1 mg), 20.17 (3 mg) and 29.52 (5 mg) mU/10 6 cells (p<0.05) without modifying the release of NO (p= NS vs. diluent). The expression of the secretory trefoil factor (TFF) assessed by RT-PCR increased slightly for TFF1 and TFF2 (p<0.05) or diminished for TFF3 (p<0.05) after chitosan feeding. Together, these results show that the initial contact of the polysaccharide with IEC triggers protective signals that could participate in the homeostasis of the epithelium.