Carotid Artery Combined With Systemic Hypothermia On ICAM-1 Expression And Nerve Function Transient Global Cerebral Ischemia

Objective To investigate the effect of intra-arterial cold saline infusion combined with surface cooling on inflammatory response and neuroprotection after global ischemia reperfusion in rats.Method120healthy, male SD rats, aged2-3months, weighing220-260g, were randomly divided into4groups. Group IR(Global cerebral ischemia/reperfusion group):modified pulsinelli4-vessel-block was conducted for15minutes to establish cerebral ischemia model; Group H(Hypothermia group):mild hypothermia (32℃-34℃) was applied via surface cooling for3hours after global ischemia/reperfusion; Group CH(Combined Hypothermia group):mild hypothermia (32℃-34℃) was applied via9ml20℃intra-arterial cold saline infusion at0.9ml/min and surface cooling and for3hours after global ischemia/reperfusion; Group S (Sham group):4vessel were exposed but without occlusion. At reperfusion of6,12,24,48hours,8rats from each group were randomly selected.After the neurological deficit score(NDS), blood sample was sampled and ICAM-1、IL-1β were determined by enzyme linked immunosorbent assay (ELISA) and ICAM-1were determined by Western blotting with4rats. Survival neurons in CA1area was counted through HE staining with the other4rats.. Result The time to reach mild hypothermia in group CH is much shorter than that in group H (t’=-23.86, P<0.05). Compared with group S, the NDS is much lower in group IR at each reperfusion time point. The NDS from group H and CH are much higher than that from group IR. NDS from group CH is much higher than that from group H.CH (F=78.59-191.90,q=4.32-11.61,p<0.01);Compared with group S, the number of survival neurons in CA1area decreased at each time point in group IR, group H and group CH. Survival neurons from group H and CH are much more than that from group IR. Survival neurons from group CH is much more than that from group H;Compared with group S, the concentration of ICAM-1、IL-1β is much higher in Group IR than that from the other groups. The concentration in group CH is higher than in group H (p>0.05) which is already lower than in group IR(F=8.11-16.89, q=2.69-4.83, P<0.05. Compared with group S, the experssion of ICAM-1is much higher in group IR than that from the other groups. The expression in group CH is higher than in group H (p<0.05)Conclusion Mild hypothermia can significantly reduce inflammation reaction. And intra-arterial cold saline infusion combined with surface cooling was proved to be a better effect against cerebral ischemia/reperfusion injury.