Features of an Expression of Smooth Muscle Actin by Muscle Cells of Arterioles and Venules of Ureter and Urinary Bladder of Newborns in Modeling Chronic Intrauterine Hypoxia

Abstract

Introduction/ Background
Chronic intrauterine hypoxia, accompanied numerous complications of pregnancy, is one of the damaging factor of the organism of fetus and newborn.

Aims
The purpose – to reveal the features of expression of smooth muscle actin by muscle cells of arterioles and venules of ureter and urinary bladder of newborns under the influence of experimental chronic intrauterine hypoxia.

Methods
An experiment was conducted on modeling high mountain hypoxia in rats of WAG line. Two groups were formed: I – newborns (n=11) born from 3 rats that were not subjected to high mountain hypoxia; II – newborns (n=10) born from 4 rats that throughout pregnancy were exposed to a daily high mountain hypoxia. The material of the study was the tissue of ureter and urinary bladder. It was used peroxidase reaction with the monoclonal antibodies to smooth muscle actin (DAKO, Denmark). The slides were studied in microscope «Olympus ВХ- 41». An experimental study was carried out in strict compliance with the requirements of the European convention (Strasbourg, 1986) on the housing, feeding and care of experimental animals, and their removal from the experiment. Mean values of indicators in groups were compared using a nonparametric U-criteria Mann-Whitney.

Results
In group I and II was observed expression of smooth muscle actin by muscle cells, forming muscle fibers
and including in the tunica media of arterioles and venules of ureter and urinary bladder, in a clear cytoplasmic staining in brown. In group I the mean values of indicators of thickness of muscle fibers in arterioles and venules of ureter were respectively (2,19±0,229)×10-6m and (1,38±0,189)×10-6m; in urinary bladder – (2,92±0,207)×10-6m and (2,11±0,160)×10-6m. In group II the mean values of indicators of thickness of muscle fibers in arterioles and venules of ureter were respectively (1,67±0,270)×10-6m and (0,88±0,107)×10-6m; in urinary bladder – (2,20±0,198)×10-6m and (1,49±0,239)×10-6m. Analyzing and comparing the obtained values, it was observed that in group I and II was determined significant predominance (р<0,05) the mean values of indicators of thickness of muscle fibers in arterioles in comparison with venules in ureter and urinary bladder. In group I was a significant (р< 0,05) prevalence the mean values of indicators of thickness of muscle fibers in arterioles and venules of urinary bladder in comparison with ureter; significant differences in group II (р >0,05) were absent. In group II in ureter and urinary bladder was a significant (р<0,05) decreasing of the mean values of indicators of thickness of muscle fibers in arterioles and venules in comparison with group I.

Conclusion: Chronic intrauterine hypoxia leads to a thinning of the thickness of the muscle fibers in arterioles and venules of ureter and urinary bladder in newborns.