Protection afforded by preconditioning to the diabetic heart against ischaemic injury (original) (raw)

1998, Cardiovascular Research

. Objective: The aim of this study was to assess whether the cardioprotective effect of ischaemic preconditioning IPC on endothelial function in coronary arteries and myocardial function is affected in the streptozotocin-induced diabetic rat heart. Methods: Isolated Ž y1 . hearts, perfused under constant flow conditions, were exposed to 30 min of partial ischaemia flow rate 1 ml min followed by 20 min Ž . Ž . of reperfusion. Results: In the diabetic group without ischaemia or IPC , infusion of 10 mM serotonin 5-HT , an endothelium-depen-Ž . dent, and 3 mM sodium nitroprusside SNP , an endothelium-independent vasodilator, in the coronary bed preconstricted with 0.1 mM U-46619 induced a marked vasodilation. Ischaemia, either without or with preconditioning with a single 5 min ischaemia and 10 min Ž . reperfusion IPC1 before ischaemia, was accompanied by a reduced 5-HT-induced vasodilation in diabetic hearts. In contrast, IPC1 preserved the response to 5-HT in non-diabetic hearts. A more extensive IPC with 3 periods of 5 min ischaemia followed by 5 min Ž . reperfusion IPC3 preserved the vasodilation produced by 5-HT in both diabetic and non-diabetic hearts. IPC3 increased the recovery of d Prdt and d Prdt during the 30 min ischaemic period and during reperfusion in all hearts. In contrast, IPC1 had no effect on max min myocardial recovery in either groups. Adenosine pre-treatment started 30 min before ischaemia mimicked IPC3, preserving the vasodilation to 5-HT and improving myocardium recovery in both groups. When adenosine was started 15 min before ischaemia, vasodilation to 5-HT was preserved in non-diabetic hearts only. Conclusions: These results suggest that IPC affords protection to endothelial function in resistance coronary arteries of diabetic hearts. To achieve this protection, a more extensive IPC is needed, which may be related to a longer exposure to adenosine. q 1998 Elsevier Science B.V.

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