Objective To investigate the effect of graded hypothermia on neuropathologic alterations of neonatal rat brain after exposed to hypoxic-ischemic insult at 37℃, 33℃, 31℃, and 28℃, respectively, and to observe the e...Objective To investigate the effect of graded hypothermia on neuropathologic alterations of neonatal rat brain after exposed to hypoxic-ischemic insult at 37℃, 33℃, 31℃, and 28℃, respectively, and to observe the effect of hypothermia on 72-kDa heat shock protein （HSP72） expression after hypoxic-ischemic insult. Methods Seven days old Wistar rats were subjected to unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 2 hours at 37℃, 33℃, 31℃, and 28℃, respectively. The brain temperature was monitored indirectly by inserting a mini-thermocouple probe into the temporal muscle during hypoxia. After hypoxia-ischemia their mortality was assessed. Neuronal damage was assessed with HE staining 72 hours after hypoxia. HSP72 expression at 0.5, 24, and 72 hours of recovery was immunohistochemically assessed using a monoclonal antibody to HSP72. Results Hypoxia-ischemia caused 10.5% （2 / 19） of mortality in rat of 37℃ group, but no death oc- curred in 33℃, 31℃ or 28℃ groups. HE staining showed neuropathologic damage was extensive in rats exposed to hypoxia-ischemia at 37℃ （more than 80.0%）. The incidence of severe brain damage was significantly decreased in 33℃ （53.3%） and 31℃ groups （44,4%）, and no histologic injury was seen in the 28℃ group of rats. Expression of HSP72 was manifest and persistent in the rat brain of 37℃ group, but minimum in the rat brain of 28℃ group. Conclusion Mild and moderate hypothermia might prevent cerebral visible neuropathologic damage associated with hypoxic-ischemic injury by decreasing stress response.展开更多
文摘Objective To investigate the effect of graded hypothermia on neuropathologic alterations of neonatal rat brain after exposed to hypoxic-ischemic insult at 37℃, 33℃, 31℃, and 28℃, respectively, and to observe the effect of hypothermia on 72-kDa heat shock protein （HSP72） expression after hypoxic-ischemic insult. Methods Seven days old Wistar rats were subjected to unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 2 hours at 37℃, 33℃, 31℃, and 28℃, respectively. The brain temperature was monitored indirectly by inserting a mini-thermocouple probe into the temporal muscle during hypoxia. After hypoxia-ischemia their mortality was assessed. Neuronal damage was assessed with HE staining 72 hours after hypoxia. HSP72 expression at 0.5, 24, and 72 hours of recovery was immunohistochemically assessed using a monoclonal antibody to HSP72. Results Hypoxia-ischemia caused 10.5% （2 / 19） of mortality in rat of 37℃ group, but no death oc- curred in 33℃, 31℃ or 28℃ groups. HE staining showed neuropathologic damage was extensive in rats exposed to hypoxia-ischemia at 37℃ （more than 80.0%）. The incidence of severe brain damage was significantly decreased in 33℃ （53.3%） and 31℃ groups （44,4%）, and no histologic injury was seen in the 28℃ group of rats. Expression of HSP72 was manifest and persistent in the rat brain of 37℃ group, but minimum in the rat brain of 28℃ group. Conclusion Mild and moderate hypothermia might prevent cerebral visible neuropathologic damage associated with hypoxic-ischemic injury by decreasing stress response.
