Cerebral Ischemia Reperfusion Injury Model

Adult male Sprague-Dawley (S.D.) rats (270–290 g) were obtained from the Laboratory Animal Unit, the University of Hong Kong. All procedures for animal care and experimental were approved by the University Committee on the Use of Live Animals in Teaching and Research (CULATR). The rats were kept in a temperature and humidity-controlled environment for 12 h dark/light cycles with free access to food and water.

Rats were subjected to middle cerebral artery occlusion (MCAO) to induce experimental cerebral ischemia-reperfusion model with the protocols as described previously with minor modification (Chen et al., 2015). Briefly, rats were anesthetized firstly with 4% isofluorane and maintained at 2% isofluorane through inhalation. A middle incision was made in the neck, followed by careful exposure of the left common carotid artery (CCA), external carotid artery (ECA), and internal carotid artery (ICA) under the microscope. A silicon-coated suture (Doccol, Redlands, CA, United States), with the diameter is 0.38 mm, was inserted from ECA to ICA, and advanced to occlude the middle cerebral artery (MCA). After 2 h of occlusion, the suture was removed and CCA was released to allow reperfusion. Sham group rats underwent the same surgical procedure without MCA occlusion. Rats body temperature were monitored during and after surgery. Rats were temporarily transferred to a cage with a heating lamp from recovery. 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining was performed to evaluate the success of the MCAO model (Chen et al., 2020).