Özet:

Diabetes plays an important role in the development of ischemic heart disease and aggravates long term outcome of the disease. In contrast to clinical data, results concerning the sensitivity to ischemia of hearts from experimental animal models of diabetes are controversial. Several factors including the duration, severity and the type of diabetes, severity of ischemic protocol (ie, global zero flow versus low-flow ischemia) and different study protocols testing the effect of ischemia (in vivo or in vitro) accounted for the conflicting results. Bradycardia is one of the functional abnormalities occuring in diabetic heart, which may cause the increased tolerance against to ischemia/reperfusion (I/R) injury. To address this point, the study was aimed to evaluate the effect of heart rate on functional recovery of diabetic rat hearts subjected to I/R injury. Isolated hearts from 8-weeks diabetic or age-matched controls were divided into spontaneously beating and paced (300 beats/min) beating groups. After 20-minute stabilization period, global ischemia(40 min) followed by reperfusion(40 min) was applied to isolated hearts. In both experimental conditions, cardiac functions before ischemic period were all depressed in diabetic hearts compared with controls. In spontaneously beating group, % recovery of hearts at the end of reperfusion in diabetic and control rats was, 80.0 ± 8.0 and 9.2 ± 4.8, respectively. In paced beating group, % recovery of diabetic and control hearts was, 66.0 ± 10.3 and 8.0 ± 4.0, respectively. This results showed that the heart from 8-week diabetic rat was resistance to I/R injury, which was independent from bradycardia

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