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Effect of mild aerobic training on the myocardium of mice with chronic Chagas disease
Emerson Preto1, Nathalia Ea Lima1, Lucila Simardi2
1Universidade São Judas Tadeu, São Paulo, SP, Brazil.
Insights
Mild aerobic exercise improved heart structure in mice with chronic Chagas disease. Physical training reduced cardiac fibrosis and inflammation, restoring ventricular parameters to levels seen in healthy controls.
Area of Science:
- Cardiovascular Physiology
- Parasitology
- Exercise Science
Background:
- Chronic Chagasic heart disease involves significant cardiovascular remodeling, including denervation, inflammation, myocyte damage, fibrosis, and hypertrophy.
- Aerobic exercise is a recognized intervention for managing various cardiovascular conditions.
Purpose of the Study:
- To investigate the effects of mild exercise on the right and left ventricles of BALB/c mice with chronic Chagas disease.
- Utilize morphometric and stereological methods to assess cardiac changes.
Main Methods:
- Twenty male BALB/c mice were divided into four groups: untrained control, trained control, untrained infected (UI), and trained infected (TI).
- Infected groups received Trypanosoma cruzi inoculation, entering the chronic phase after 40 days.
- The trained groups underwent 8 weeks of daily swimming exercise (30 minutes/day, 5 days/week) at 30°C. Cardiac tissues were analyzed using hematoxylin-eosin and picrosirius red staining.
Main Results:
- Physical training increased capillary volume density and decreased collagen fiber volume density and cardiomyocyte cross-sectional area in trained infected (TI) mice.
- Histopathological analysis revealed reduced inflammatory infiltrate in the TI group compared to untrained infected mice.
- The exercise program facilitated recovery of cardiac parameters in the TI group.
Conclusions:
- Low-intensity aerobic exercise positively impacts morphological and morphometric parameters of the ventricles in Trypanosoma cruzi-infected mice.
- Exercise mitigates Chagas disease-induced cardiac alterations, normalizing ventricular characteristics towards those of uninfected controls.
Background:
Chronic chagasic heart disease represents extensive remodeling of the cardiovascular system, manifested as cardiac denervation, interstitial mononuclear infiltrate, myocyte and vascular degenerative changes, fibrosis, and hypertrophy. Moreover, aerobic exercises are widely indicated for the treatment of various disorders of the cardiovascular system.
Purpose:
To evaluate the right and left ventricles of BALB/c mice with chronic Chagas disease, undergoing mild exercise, by using morphometric and stereological methods.
Materials And Methods:
A total of 20 male mice at 4 months of age were used for experiments. The animals were divided into four groups (n=5 in each group): untrained control, trained control, untrained infected (UI), and trained infected (TI). Animals of UI and TI groups were inoculated with 1,000 trypomastigote forms of Trypanosoma cruzi (Y strain), and after 40 days, animals entered chronic phase of the disease. Physical exercise, which included swimming, was performed for 30 minutes daily, five times a week for 8 consecutive weeks at a bath temperature of 30°C. After the trial period, euthanasia and subsequent withdrawal of the heart were done. The organ was prepared by histological staining procedures with hematoxylin-eosin and picrosirius red.
Results:
We found that the physical training used in our experimental model promoted increase in volume density of capillaries and decrease in volume density of collagen fibers and cross-sectional area of cardiomyocytes in chagasic animals (TI group). By histopathological analysis, we found differences in the inflammatory infiltrate, which was lower in animals of TI group. The training program promoted a recovery of these parameters in the TI group.
Conclusion:
Our results suggest that low-intensity aerobic exercise acts on morphological and morphometric parameters of the left and right ventricles in mice infected with T. cruzi, reducing the changes caused by the organism and making the results comparable to those of the uninfected control group.
