Scientific Online Resource System

Scripta Scientifica Medica

A correlation between postnatal changes in the expression of nitric oxide synthase (NOS) in the rat myocardium and its morphological characteristics

A. Iliev, G. Kotov, B. Landzhov, L. Jelev, I. Dimitrova, D. Hinova-Palova

Abstract

The constitutive production of nitric oxide (NO) by the different isoforms of the enzyme nitric oxide synthase (NOS) is a major factor in the regulation of cardiac function under physiological and pathological conditions alike. As such, it affects various manifestations of the process of myocardial aging in the postnatal period, includ­ing hypertrophy and fibrosis of the ventricles and their remodelling, impaired relaxation and decreased cardiac output. The aim of the present study was to establish whether a correlation exists between changes in the expres­sion of neuronal NOS (nNOS) and the morphological characteristics of the myocardium during various periods of postnatal development. We used fifteen male Wistar rats, distributed in five age groups - 2 weeks old, 1 month old, 3 months old, 6 months old, and 12 months old, each group containing 3 animals. We used routine haematox­ylin and eosin staining and specific immunohistochemical staining for nNOS. During the early postnatal period (1-3 months), we observed a normal histological appearance of the cardiomyocytes and the interstitial space. As aging progressed (6-12 months), we reported the presence of cardiomyocytic hypertrophy, with narrowing of the interstitial space, focal myocytolysis and pronounced accumulation of collagen fibres. The immunohistochemi­cal staining for nNOS revealed that enzyme activity intensified over the course of postnatal development. It was distributed heterogeneously in the various layers of the myocardium and we noted differences in the enzyme ex­pression between the left and the right ventricle.

In conclusion, the increased expression of nNOS in senescent rats probably represents a protective mechanism against age-related hypertrophy of the cardiomyocytes. Further studies could possibly establish the importance of regional differences in enzyme expression within the myocardium.





DOI: http://dx.doi.org/10.14748/ssm.v49i0.4817
Array
Article Tools
Email this article (Login required)
About The Authors

A. Iliev
Medical University of Sofia
Bulgaria

G. Kotov
Medical University of Sofia
Bulgaria

B. Landzhov
Medical University of Sofia
Bulgaria

L. Jelev
Medical University of Sofia
Bulgaria

I. Dimitrova
Medical University of Sofia
Bulgaria

D. Hinova-Palova
Medical University of Sofia
Bulgaria

Font Size


|