Hypoxic-Ischemic Brain Damage Model

HI was imitated by unilateral ligation of the common carotid artery (CCL) followed by 2.5 h of hypoxia in 7-day-old SD rats. Rat pups were anesthetized with isoflurane (2.5%) and supine fixed in the thermostat console. A longitudinal midline incision disinfected by iodophor disinfectant was made in the anterior neck. After the right common carotid artery was identified and freed from the surrounding tissues, without any damage to the right vagus nerve, it was double ligated and transected between the ligatures. The pups were then returned to a heating pad for 1 h for recovery. Simultaneously, an airtight chamber containing 7% humidified oxygen and 93% N₂ was prepared using a heating pad to maintain the temperature at 35–39 °C. Then the HI animals were placed in the chamber for 2.5 h. Sham animals received an incision but did not undergo CCL treatment, and the pups were placed in a similar container but not exposed to a hypoxic environment. After modeling, all pups were returned to their dams. NGR1 (15 mg/kg q 12 h, for 2 days) [19] was administered to the pups by intraperitoneal injection after CCL immediately, before exposure to the hypoxic environment. ICI-182780 (2 mg/kg) was administered to pups 2 h before CCL treatment by intraperitoneal injection [19].