Background It has been found that cardiac protection afforded by ischemic preconditioning （IPC） is significantly reduced in the senescent myocardium. ADAMTS-1 （a disintesrin and metalloprotease with thrombospondin type 1 motifs） has been shown to inhibit angiogenesis in a variety of in vitro and in vivo assays. The aim of this study was to investigate the age-associated differences in ADAMTS-1 protein expression in rat myocardium after ischemic preconditioning. Methods Sixty-four young （4 months） and old （24 months） male Sprague-Dawley rats were randomly assigned to an IPC group （40 rats） or a sham group （rats）. A model of delayed IPC was induced and rats were sacrificed and myocardial samples were harvested from the ischemic-reperfused region for immunohistochemical detection of ADAMTS-1 at serial time points after IPC. A model of myocardial infarction was produced by ligation of the left anterior descending coronary artery in additional sets of young and old rats after sham or IPC procedures, then age-associated myocardial infarction survival after IPC was calculated. Results ADAMTS-1 expression increased significantly in old rats compared to young rats （P 〈0.05）. The mean densities of ADAMTS-1 protein at 0, 6, 12, and 24 hours in young-IPC group after IPC were 0.05＋0.01, 0.13±0.03, 0.16±0.04, and 0.12±0.03 vs. 0.07±0.03, 0.20±0.03, 0.24±0.05, and 0.21±0.04 in old-IPC group. IPC resulted in diminished survival rates （5/35 vs. 6/14, old-IPC group vs shortening （（13.9±2.8）% vs. （18.3±2.3）%, P 〈0.05） and old-sham group, P 〈0.05）, reduced left ventricular fractiona increased the myocardial infarction size （（37.9±3.2）% vs （32.8±5.1）%, P 〈0.05） in the older rats. Conclusions Cardioprotection with IPC is attenuated in the older heart. ADAMTS-1 expression induced by IPC is greater in old rats. Over-expression of anti-angiogenic factors might be a potential mechanism behind reduced protection after IPC associated with aging.
