Effects of transcranial magnetic stimulation on motor cortical excitability and neurofunction after cerebral ischemia-reperfusion injury in rats.

To clarify the effects of repetitive transcranial magnetic stimulation (rTMS) on rat motor cortical excitability and neurofunction after cerebral ischemia-reperfusion injury.After determined awake resting motor threshold (MT) and motor evoked potentials (MEPs) of right hindlimbs, 20 Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) reperfusion injury, then rTMS were applied to rTMS group (n=10) at different time, while control group (n=10) received no stimulation. A week later, MT and MEPs were evaluated again, as well as neurological deficits and infarct volume. The effects of rTMS and MCAO reperfusion injury on these parameters were analyzed.After MCAO reperfusion, both MT level and neurological deficit scores increased, distinct focal infarction formed, and latency of MEP elongated. Compared with the control group, the increased extent of MT and neurological scores of rats receiving rTMS were significantly lower (P < 0.05), as well as the infarct volumes reduced significantly (P < 0.05). But MEP was not affected by rTMS obviously. There was a positive linear correlation between postinjury MT and infarct volume (r = 0.64, P < 0.05).rTMS may facilitate neurofunction recovery after cerebral ischemia-reperfusion. Postinjury MT could provide prognostic information after MCAO reperfusion injury.