[Reactive changes in the smooth muscle tissue of the rat small intestine during experimental intestinal obstruction].

Using light, electron microscopy and immunohistochemical methods, the reactive transformation of smooth muscle tissue (SMT) was studied in the intestinal wall during the development of acute partial high intestinal obstruction. The material of small intestine was taken from 10 male rats in both the zone of ligature application, and proximal and distal zones, 3 cm distant from the ligation zone. The results of the study demonstrate that in partial intestinal obstruction, the nature of structural and functional SMT transformation was variable depending upon differences in functional and destructive loads. During these changes, the remodeling of smooth myocyte population was shown to be one of the mechanisms of SMT adaptation to the changing conditions of functioning. Immunohistochemical analysis found no changes in the pattern of expression of marker and phenotypic proteins in the intestinal zones studied during the dynamics of an experiment.

[Mechanisms of the contractile activity control in smooth muscle cells].

A comparative analysis of the basal level of the cytoplasmic calcium concentration in the intact intestinal isolated smooth muscle cells (SMC) of different phenotypes and the dynamic changes of its concentration in the SMC during the stimulation of their contraction, was performed. In this study, the SMC were isolated from the proximal colon, using collagenase dissociation. Confocal and fluorescence microscopy with the fluorescent probes Fura-2AM, to study the concentration of Ca2+ and MitoTracker Red, to study the activity of mitochondria, were used. It was found that the different phenotypes of visceral SMC, despite some differences in the basal levels of the cytoplasmic Ca2+ concentration, were characterized by the similar calcium response during the contraction stimulation, which indicates the identity of the mechanisms triggering contractile activity in different types of SMC.

[Response mechanisms of the airway smooth muscle tissue in experimental bronchial spasm].

This investigation was aimed at the complex evaluation of the reactivity mechanisms of bronchial smooth muscle tissue (SMT) in experimental bronchial spasm. Morphometric, cytospectrophotometric and electron microscopical analysis demonstrated the presence of three types of smooth muscle cells (SMC) within the bronchial SMT (small, medium, large), that differed in their linear and metabolic parameters. The findings of this study indicate that under the conditions of experimental bronchial spasm development, the ratios of SMC in bronchial SMT are changed with the increase in proportion of small SMC and the elimination of large SMC. In the dynamics of experimental bronchial spasm development, the activation of cytoplasmic synthesis as well as of DNA synthesis was detected mainly in group of small SMC. The reactive-dystrophic changes were marked at the subcellular level, that were most often identified in large SMC resulting in their elimination from population in the dynamics of an experiment. The data obtained suggest that one of the important mechanisms of airway SMT adaptation to the bronchial spasm development is a dynamic reorganization of SMC population.