Instilación intratraqueal de elastasa en la rata: Cambios electroforéticos de la á1-AT-antitripsina en el lavado broncoalveolar

Abstract

Introduction: Endogenous alphal-antitrypsin ( á1-AT) is the main inhibitor of the intratracheally instilled elastase in experimental animals. Objective: To evaluate by electrophoresis and immunodetection using western blot analysis, the different forms of á1-AT in bronchoalveolar lavage fluid (BALF) of Sprague Dawley rats after intratracheal instillation of elastase, with the hypothesis that the previously observed increment in antielastase activity is due to high levels of active á1-AT. Results: In the first hours after elastase instillation the concentration of á1-AT increases more than seven times due to an increase in alveolar-capillary permeability. á1-AT in BAIF is found as the native protein (~ 52 kDa), as complexes of different molecular sizes (> 75 kDa and > 100 kDa) and as a proteolytic product (< 40 kDa). Conclusion: In spite of a high proportion of á1-AT in the inactive form as part of different complexes, the increase in alveolar-capillary permeability after elastase treatment contributes to maintain high levels of active á1-AT. These results could be of importance in other inflammatory lung processes.