Comparative study of the two types of limb remote ischemic per-conditioning on the brain protection

Background Limb remote ischemic per-conditioning (LRPC) has been recognized as an applicable strategy in protecting against cerebral ischemia-reperfusion injury. However, widely used invasive limb remote ischemic per-conditioning (LRPC-I) is traumatic, limiting the possibility of long-term application and making it more difficult to achieve the conversion from basic research to clinical practice. Because of this, if non-invasive limb remote ischemic per-conditioning (LRPC-N) has the same effect of brain protection as LRPC-I, it may be more beneficial to clinical practice. Methods The middle cerebral artery occlusion (MCAO) ischemia-reperfusion injury model was established by the suture method in mice. In the beginning of the ischemia, the LRPC-I and LRPC-N were respectively carried out by three cycles of 10 min distal airbag pressurization or clamping the distant limb artery (ischemia) /10 min reperfusion. Neurological functional deficits after procedure were evaluated, and the cerebral infarct volumes and the degree of cerebral edema were quantified by TTC staining. Results Compared with the control group, the neurological functional outcomes of LRPC-N group and LRPC-I group were improved significantly (P = 0.041, 0.035); the edema volumes were much smaller (P = 0.040, 0.028); the infarct volumes reduced significantly (P = 0.001, 0.019). However, there were no significant differences between LRPC-N group and LRPC-I group on the functional neurological outcomes, edema volumes and the infarct volumes (P = 0.754, 0.946, 0.667). Conclusion Both the LRPC-N and LRPC-I have protective effects on animal models of cerebral ischemia⁃reperfusion injury, and there is no obvious difference between each other.