Changes in ischemic tolerance and effects of ischemic preconditioning in middle-aged rat hearts

Masato Tani, Yukako Suganuma, Hiroshi Hasegawa, Ken Shinmura, Yoko Hayashi, Xiao Dong Guo, Yoshiro Nakamura

研究成果: Article査読

104 被引用数 (Scopus)

抄録

Background: Although both clinical and animal studies have shown that ischemic tolerance is reduced in the senescent myocardium, it has not been clarified when myocardium becomes more vulnerable to ischemia. Preconditioning protects the hearts of young adult animals of various species, but its effects are not identical in human studies. We investigated whether ischemic tolerance and the effect of preconditioning decreased in isolated hearts of middle-aged rats. Methods and Results: The hearts of young adult rats 112 weeks old: group Y, n=44) and middle-aged rats (50 weeks old: group M, n=44) were subjected to global ischemia for 15, 20, or 25 minutes followed by reperfusion. Hearts were also subjected to preconditioning and then to 2 (group Y, n=22) or 15 (group M, n=22) minutes of ischemia followed by reperfusion. Left ventricular developed pressure (LVDP) was decreased by 40% to 60%, and the level of ATP was decreased by 60% to 70% in group M compared with group Y. Preconditioning increased LVDP (% LVDP, 40,5% to 72.4%) and levels of high-energy phosphates (ATP, 11.8 to 14. 1; creatine phosphate, 17.0 to 23.1 μmol/g dry wt) and reduced left ventricular end- diastolic pressure (LVEDP, 32.8 to 10.3 mm Hg), creatine kinase release (257 to 132 U/g dry wt), and ryanodine-sensitive sarcoplasmic reticulum Ca2+ release after ischemia in group Y. Preconditioning exerted opposite effects in group M (% LVDP, 45.9% to 15.8%; LVEDP, 21.0 to 28.5 mm Hg; ATP, 14.1 to 8.5 μmol/g dry wt; and CK release, 176 to 332 U/g dry wt). Preconditioning was associated with increases in the incidence of reperfusion induced ventricular fibrillation (0% to 62.5%) and the rate of sarcoplasmic reticulum Ca2+ release in group M. Conclusions: These results indicate that hearts became more vulnerable to ischemia with age and that the beneficial effects of preconditioning were reversed in middle-aged rat hearts.

本文言語English
ページ(範囲)2559-2566
ページ数8
ジャーナルCirculation
95
11
DOI
出版ステータスPublished - 1997
外部発表はい

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

フィンガープリント 「Changes in ischemic tolerance and effects of ischemic preconditioning in middle-aged rat hearts」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル