Peculiarities of synthesis of matrix metalloproteinase-9 in the lungs during experimental development of distress syndrome

Abstract

Acute respiratory distress syndrome (ARDS) was reproduced in nonlinear male rats by intratracheal instillation of 45—55 thousand, lysate rat neutrophils (method patented in RF); the control group was injected with saline solution. The animals were taken from the experiment at 1, 3 and 6 days, the expression of matrix metallopro-teinase-9 (MMP-9) by cells of the lungs was determined, by immunohistochemistry at each days. The expression of MMP-9 was found in neutrophils, macrophages, fibroblasts, endothelium and. type 2 alveolocytes in the both groups. In the control group the expression, of MMP-9 was found equally low in the all cells, except type 2 alveolocytes. It was decreased in type 2 alveolocytes on day 6. A significant increase in the expression of MMP-9 was found in neutrophils, macrophages, fibroblasts endothelium and type 2 alveolocytes in the exudative stage of ARDS. In the proliferative stage the expression of MMP-9 was high in all the cells, decreasing only in type 2 alveolocytes. In the fibrotic stage of expression of MMP-9 returned to the level of the control group in macrophages, type 2 alveolocytes, the endothelium; in neutrophils and fibroblasts it remained high.