Spinal cord stimulation produced vasodilation in streptozotocin‐induced diabetic rats

Abstract

Spinal cord stimulation (SCS) is used to improve peripheral circulation in selected patients with peripheral arterial diseases (PAD). It is unclear whether SCS is effective for PAD in diabetic patients. This study investigated the effects of SCS on peripheral circulation in diabetic rats. Male rats, 8–9 weeks of age, were injected with streptozotocin (50 mg/Kg in 10 mM citrate buffer, ip), or citrate buffer as control. Four weeks later, SCS-induced vasodilation was tested. A unipolar ball electrode was placed on left or right dorsal column at spinal cord lumbar 2–3 segments in pentobarbital anesthetized, paralyzed and ventilated rats. Cutaneous blood flows from right and left hind foot pads were recorded. SCS was applied through a ball electrode at 30%, 60% and 90% of motor threshold (MT). MT was greater in diabetic rats than control rats (494±47 μA vs 376±12 μA, P<0.05, n=7). SCS-induced vasodilation was attenuated at 90% of MT (118.6±12.3 % vs 189.2 ±30.6 %, P<0.05, n=13), but not at 30 and 60% of MT in diabetic rats compared to control rats. Furthermore, increasing SCS from 30% to 90% typically produced a progressive increase in blood flow in control rats but not in diabetic rats (11/13 vs 2/13, P<0.01, n=13). This study suggested that pathways of SCS–induced vasodilation were impaired, but still improved peripheral blood flow in the diabetic condition. (NIH grant HL075524 & NS35471 and AHA Predoctoral Fellowship 0615642Z)