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This Article Full Text Full Text (PDF) All Versions of this Article: 285/4/H1521    most recent 00890.2002v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Husse, B. Articles by Isenberg, G. Search for Related Content PubMed PubMed Citation Articles by Husse, B. Articles by Isenberg, G.

Cyclical mechanical stretch-induced apoptosis in myocytes from young rats but necrosis in myocytes from old rats

Department of Physiology, Martin-Luther-University Halle, D-06097 Halle, Germany

Submitted 11 October 2002 ; accepted in final form 10 June 2003

Mechanical load as stimulus for apoptosis and necrosis could be responsible for the loss of cardiomyocytes. Ventricular myocytes from young (3 mo) and old (14–24 mo) rats underwent cyclical mechanical stretch (CMS; 5% elongation, 1 Hz) for 24 h. Spontaneous apoptosis was in myocytes from young rats 0.33 ± 0.12% and from old rats 1.05 ± 0.35% [Tdt-mediated dUTP nick-end labeling (TUNEL) assay]; associated with a decrease of Bcl-2. CMS increased the apoptosis to 0.58 ± 0.18% in myocytes from young rats. Western blot analysis showed that CMS reduced Bcl-2 and increased p53 (young rats). Bax was not changed by CMS. These were confirmed by cytochrome c release (31 ± 13%) and by the enrichment of cytosolic nucleosomes (11 ± 8%). CMS did not influence the apoptosis in myocytes from old rats (TUNEL assay, Bcl-2, Bax, or p53). CMS did not cause necrosis in myocytes from young rats. CMS increased the number of necrotic cells by showing the cell membrane rupture in myocytes from old rats (50 ± 13% 5-hexadecanoylaminofluorescein-positive and 38 ± 6% propidium iodide-positive cells) as well as by measuring the lactate dehydrogenase release. The results suggest that CMS-induced apoptosis in myocytes of young rats but necrosis in myocytes from old rats, which could be attributed to more stress sensitivity of cells from old rats.

ventricular myocytes; age

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