Keywords: 
• adenosine /
• preconditioning /
• ischaemia-reperfusion injury

Abstract: OBJECTIVE To investigate the protective effects of preconditioning on cardiac and pulmonary injury induced by lower extremity ischaemia-reperfusion in rats METHODS Animals were randomized into 4 groups and underwent laparotomy The abdominal aorta was isolated and clamped below the renal artery level for 120min then declamped for another 120min Group Ⅰ(n=8)was taken as control Group Ⅱ(n=8) was pretreatedwith ischaemia preconditioning that the lower extremities had experienced 4 times of ischaemia and reperfusion 5 min each before the 240 min treatment began Group Ⅲ(n=8) accepted continuous drip infusion of adenosine Group Ⅳ(n=8)was sham operated All groups were given Evan's blue dye intravenously after anesthesia Mean artery pressure(MAP), myocardium ATP_ase activities and malonyldiadehyde(MDA), pulmonary MDA and Evan's blue were determined separately. RESULTS MAP was lower in groupⅠand Ⅲ than in Ⅱ and Ⅳ,neither group Ⅰand Ⅲ, norⅡand Ⅳ, had significant differences(Ⅰ:61±14;Ⅱ:86±12; Ⅲ:69±18;Ⅳ:94±23mmHg) Myocardium ATP_ase activity was lower in group Ⅰthan in group Ⅱ,Ⅲ,Ⅳ(Na⁺ K⁺ ATP_ase 8.1±0.4 vs 8.9±2.1, 9.4±1.0and 9.0±0.8U/mg; Ca²⁺ ATP_ase 5.0±0.2 vs 5.3±1.0, 5.9±0.7and 5 7±0 8U/mg; Mg²⁺ ATP_ase 4.4±0.3 vs 5.2±0.8, 5.1±0.71and 5.3±0.6 U/mg),the MDA level was higher in groupⅠthan in group Ⅱ,Ⅲ,Ⅳ(MDA 2.5±0.4 vs 1.8±0.7, 1.6±0.5 and 1.7±0.7nmol/mg) Pulmonary MDA and Evan's blue level were higher in group Ⅰthan in the other three groups(MDA 2.3±0.2vs 1.6±0.4, 1.8±0.5 and 1.4±0.6nmol/mg; Evan's blue 3.1±1.2 vs 1.6±0.5, 1.5±0.3and 0.9±0.2μ_g/mg) CONCLUSION Ischaemia and adenosine preconditioning have some protective effects on cardiac and pulmonary injury induced by ischaemia reperfusion of lower extremity in rats.