Role of heme oxygenase-1 in hemopexin-induced reduction of cerebral ischemia-reperfusion injury in rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of heme oxygenase-1 (HO-1) in hemopexin (HPX)-induced reduction of cerebral ischemia-reperfusion (I/R) injury in rats.Methods:One hundred and eighty male Sprague-Dawley rats, aged 7-8 weeks, weighing 250-280 g, were divided into 5 groups ( n=36 each) using a random number table method: sham operation group (group SH), I/R group, vehicle group (group V), HPX group, and HPX plus HO-1 specific inhibitor ZnPPIX(HZ group). Local cerebral I/R was produced by middle cerebral artery occlusion for 120 min followed by reperfusion in anesthetized rats.In I/R, V, HPX and HZ groups, 0.9% normal saline 10 μl, 0.1% NaN 3 10 μl, 1.86 g/L HPX (diluted to 10 μl in 0.1% NaN 3 solution), and 1.86 g/L+ ZnPPIX 20 μmol/L (diluted to 10 μl in 0.1% NaN 3 solution) were injected through the lateral ventricle, respectively, immediately after onset of reperfusion.Morris water maze test was used to detect the cognitive function on day 1 before ischemia and day 2 of reperfusion.Rats were sacrificed, brains were removed and brain tissues were obtained for determination of the permeability ratio of Evans blue (EB), brain water content, expression of VE-cadherin in ischemic penumbra (by Western blot), and expression of angiopoietin-1 (Ang1) mRNA and Ang2 mRNA (by real-time polymerase chain reaction). Ang1 mRNA/Ang2 mRNA ratio was calculated.CD31/vWF double labeling immunofluorescence was used to detect the density of neovascularization in hippocampal tissues in the ischemic penumbra. Results:Compared with SH group, the escape latency was significantly prolonged at 2-7 days of reperfusion, the percentage of time of staying at the target quadrant was decreased, the frequency of crossing the platform was decreased, the permeability ratio of EB in brain tissues was increased at day 7 of reperfusion, and the brain water content, Ang1 mRNA/Ang2 mRNA ratio, expression of VE-cadherin and density of neovascularization were decreased in I/R, V, HPX and HZ groups ( P<0.05). Compared with I/R group, the escape latency was significantly shortened at 2-7 days of reperfusion, the percentage of time of staying at the target quadrant was increased, the frequency of crossing the platform was increased, the permeability ratio of EB in brain tissues was decreased at day 7 of reperfusion, and the brain water content, Ang1 mRNA/Ang2 mRNA ratio, expression of VE-cadherin and density of neovascularization were increased in HPX group ( P<0.05), and no significant change was found in the parameters mentioned above in V and HZ groups ( P>0.05). Compared with HPX group, the escape latency was significantly prolonged at 2-7 days of reperfusion, the percentage of time of staying at the target quadrant was decreased, the frequency of crossing the platform was decreased, the permeability ratio of EB in brain tissues was increased at day 7 of reperfusion, and the brain water content, Ang1 mRNA/Ang2 mRNA ratio, expression of VE-cadherin and density of neovascularization were decreased in HZ group ( P<0.05). Conclusion:HO-1 is involved in HPX-induced reduction of cerebral I/R injury in rats.