2.2. Rat model of cerebral stroke

A cerebral ischemic rat model²⁰ was employed to investigate the effect of RIPostC on brain functional recovery. Male Sprague–Dawley rats (250‐300 g) were obtained from Shanghai SIPPR‐BK LAB Animal Ltd., Shanghai, China (license number: SCXK (Hu) 2013‐0016) and were housed under diurnal lighting conditions (12 hours darkness/light). Experiments were performed according to the Institutional Animal Care and Use Committee of Fudan University (Shanghai, China). The experimental protocol was approved by the Department of Laboratory Animal Science, Fudan University (approval number: 20140143C001). To generate MCAO model, rats were anesthetized with 10% chloral hydrate (0.36 mL/100 g, intraperitoneal). The body temperature of the rats was maintained at 37°C with a heating pad. Surgical procedures for MCAO and reperfusion were performed as previously reported.²⁰ Briefly, a midline incision about 2 cm was made in the neck skin, and the left carotid artery, external carotid artery, and internal carotid artery were carefully isolated. A filament with a poly‐L‐lysine coated blunted tip was used to occlude rats’ left middle cerebral artery. The length of the filament inserted through the internal carotid artery was approximately 20 mm. The blood flow was monitored using laser Doppler anemometry (Moor Instruments Ltd, Miuwev AxIllinster, EXl3 5HU, UK) to make sure its loss reached 70% to 80%. After a 1.5‐hour occlusion, the filament was withdrawn and reperfusion was established. After recovering from anesthesia, the neurologic deficits were measured with a five‐point scale. Rats with scores of 1‐3 were considered successful models and included in the study and the rats with a score of 0 or 4 were excluded from the study. Rats in the sham‐operated group underwent the MCAO procedures without insertion of the filament and occlusion of the middle cerebral artery.