Analysis of the effects of a continuous magnetic field on the heart and diaphragm of elderly Wistar rats

Introduction and aim. The aim was to investigate the histomorphometric effects of applying a static magnetic field (MF) of different intensities to the diaphragm muscle and heart of aging rats. Material and methods. Continuous MF of three different intensities were applied for five consecutive days (10 hours in total). Morphological and histological variables in the diaphragm and heart were assessed, including capillary density, cardiomyocyte diameters, histopathological index, and the presence of regenerative changes. Results. In the diaphragm, there was a significant reduction in the number of capillaries in the treated groups (p<0.05), with no changes in the other morphological variables (p>0.05). In the heart, there were no differences in cardiac mass or in the heart weight/body weight ratio (p>0.05), indicating no macroscopic hypertrophy. However, the intensity of 2500 G led to an increase in the area of the cardiomyocytes and their nuclei (p<0.05), suggesting an adaptive response to the overload. There were no significant changes in the histopathological index or in muscle degeneration characteristics (p>0.05). Conclusion. Exposure to MF influenced the microcirculation of the diaphragm and promoted cellular changes in the heart, especially at higher intensities, without causing apparent damage to the tissue.