Effects of Trypanosoma cruzi infection on myocardial morphology, single cardiomyocyte contractile function and exercise tolerance in rats.
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2011
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The aim of this study was to investigate the effects of Trypanosoma cruzi (T. cruzi)
infection on myocardial morphology, single cardiomyocyte contractile function and
exercise tolerance in rats. Adult Wistar rats were randomized into control (n = 14)
and infected (n = 14) groups. Infected animals were inoculated with T. cruzi Y strain
(300,000 trypomastigotes ⁄ 50 g body weight). After 9 weeks, the animals were subjected
to a treadmill running protocol. Then, the right atrium (RA) and left ventricle
(LV) were removed for morphological and cell contractile evaluation. The infected
animals exhibited a significant reduction in distance travelled, total time to fatigue
and workload. In addition, these animals had hypertrophy, increased myocardial cellularity,
and an increase in the proportion of collagen and blood vessels. RA and LV
myocytes from infected animals showed marked contractile dysfunction under basal
conditions and a reduced contractile response to b-adrenergic stimulation. The workload
of infected animals was correlated closely with the amplitude of cell shortening
of RA and LV myocytes. T. cruzi infection influenced the myocardial morphology
and the mechanical properties of RA and LV single myocytes negatively and reduced
exercise tolerance. Single cardiomyocyte contractile dysfunction could constitute an
additional mechanism of cardiac impairment and reduced exercise tolerance in this
infection.
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Cellular contractility, Myocytes, Physical capacity
Citação
NOVAES, R. D. et al. Effects of Trypanosoma cruzi infection on myocardial morphology, single cardiomyocyte contractile function and exercise tolerance in rats. International Journal of Experimental Pathology, v. 92, p. 299-307, 2011. Disponível em: <http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2613.2011.00781.x/abstract>. Acesso em: 19 fev. 2017.