[Stereology of the myocardium in young and aged rats].

Autor:	Aguila MB; Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro-UERJ., Mandarim-de-Lacerda CA, Apfel MI
Jazyk:	portugalština
Zdroj:	Arquivos brasileiros de cardiologia [Arq Bras Cardiol] 1998 Feb; Vol. 70 (2), pp. 105-9.
Abstrakt:	Purpose: To determine the myocardial quantitative changes comparing young and aged animals by using the stereology. Methods: Thirty rat hearts were studied (15 rats aged 3 months and 15 other rats aging 15 months). The hearts were removed, weighed, fixed in 10% buffered formaldehyde solution, embedded in paraffin, cut in 7 microns thick slices and stained with HE and picro-sirius stains. In each group, we counted 15 random microscopic fields. The following parameters were studied: Vv (myocyte) and Vv(interstitium)(%) (the volume densities of the cardiac myocyte and interstitium, determined by the point-counting method), and Nv(myocyte) (1/mm3) (the numerical density of the cardiac myocytes, determined with the disector method). The total number of myocytes (N[myocyte]) and the mean volume of the myocytes (V[myocytes]) were also determined. The differences were tested by the Mann-Whitney test. Results: Cardiac weight increased from 1.1 to 1.7 g, the Vv(myocyte) decreased from 76.7 to 72.2%, the Vv(interstitium) increased from 23.3 to 27.8%. The Nv(myocyte) and the N(myocyte) decreased from 14.76 x 10(4) to 6.19 x 10(4)/mm3 and 15.64 x 10(4) to 10.72 x 10(4) myocytes, respectively. Simultaneously, the V(myocyte) increased from 5.42 x 10(3) to 13.26 x 10(3) mm3. These differences were statistically significant (p < 0.05). Conclusion: Myocardial changes, comparing young rats with aged ones suggest loss of myocytes (increased apoptosis?) with simultaneous myocyte hypertrophy.
Databáze:	MEDLINE
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