Recent studies have showed that pretreatment with short episode spinal cord stimulation (SCS) could reduce myocardial infarct size after transient anterior coronary artery occlusion. The aim of this study was to investigate whether continuous SCS could also provide protection against cardiac ischaemia/reperfusion (IR) injury.

After pre-implantation of stimulating electrode, Sprague-Dawley rats with or without pretreatment by a five consecutive days of SCS were assigned into SCS and control groups (CTRL). Additional rats without electrode implantation were allocated into the IR and SHAM groups. Twenty-four hours after pretreatment, the hearts were basal perfused on Langendorff apparatus for 30min and then subjected to 50-min ischaemia and 120-min reperfusion. Left ventricular (LV) function, infarct size, myocardial enzyme release, and myocardial apoptosis were measured.

Pretreatment with continuous SCS significantly improved LV function and reduced infarct size and cardiac enzyme release. The myocardial apoptosis in the SCS group was also remarkably inhibited. In addition, the expressions of Bax and caspase-3 were markedly reduced, and the expression of Bcl-2 and ratios of Bcl-2/Bax were greatly enhanced after continuous pretreatment.

Pretreatment with continuous SCS provided prolonged protection against cardiac I/R injury and the underlying mechanism included regulation of the apoptosis-related proteins.