Abstract

CASTRO, DR; FERREIRA, JC; BRUM, P  and  DUARTE, JA. Age-induced cardiac muscle ultra-structural changes in the animal model. Rev. Port. Cien. Desp. [online]. 2009, vol.9, n.2-3, pp.141-149. ISSN 1645-0523.

The purpose of this work was to characterize, in the animal model, the cardiac muscle ultra-structural changes associated to biological aging process. The sample were 31 male mice, aged 3 months (n=13) and 7 months (n=18). After sacrifice, each animal was removed from the heart with subsequent processing of the left ventricular wall for analysis of transmission electron microscopy. The number, frequency and areas of the mitochondria and granules of lipofuscin / residual corpuscles were quantified by scanning of the obtained photographs. The results showed a higher mitochondrial heterogeneity and size of these organelles, for the various percentiles studied in animals of 7 months. Regarding the frequency of mitochondria by cellular area, there were no significant differences between groups (3 months: 0.97 ± 0.31 vs. 7 months: 1.03 ± 0.55, p> 0.05). Also there were no changes in mitochondrial density (3 months: 42.10% ± 9.64 vs. 7 months: 45.17% ± 18.38, p> 0.05). The lipofuscin granules / residual corpuscles did not increase in size or changed their cellular density with age (3 months: 0.35 ± 0.51 vs. 7 months: 0.67 ± 1.12, p> 0.05); however, their frequency, by cell area was significantly higher in animals of 7 months (3 months: 0.11 ± 0.21 vs. 7 months: 0.16 ± 0.16, p <0.05). From results it is possible to conclude that are already evident degenerative cellular changes in 3 months aged animals, which worsen with aging. It can also be concluded that the area of cardiac mitochondria tends to increase with age, despite its cell density has remained fairly constant.

Keywords : aging; cardiac muscle; mitochondria; granules of lipofuscin; residual corpuscles.

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