首页|期刊导航|中华医学杂志（英文版）|Hemin, a heme oxygenase-1 inducer, improves aortic endothelial dysfunction in insulin resistant rats
中华医学杂志（英文版）2008，Vol.121Issue(3)：241-247,7.
Hemin, a heme oxygenase-1 inducer, improves aortic endothelial dysfunction in insulin resistant rats
Hemin, a heme oxygenase-1 inducer, improves aortic endothelial dysfunction in insulin resistant rats
摘要
Abstract
Background Under an insulin resistance(IR)state,overproduction of reactive oxygen species(ROS)may be playing a maior role in the pathogenesis of endothelial dysfunction,hypertension and atherosclerosis.Recently,increasing attention has been drawn to the beneficial effects of heme oxygenase-1(HO-1)in the cardiovascular system.This study aimed to investigate the effects of HO-1 on vascular function of thoracic aorta in IR rats and demonstrate the probable mechanisms of HO-1 against endothelial dysfunction in IR states.Methods Sprague-Dawley (SD) rats fed with high-fat diet for 6 weeks and the IR models were validated with hyperinsulinemic-euglycemic clamp test.Then the IR rat models (n=44) were further randomized into 3 subgroups,namely,the IR control group (n=26, in which 12 were sacrificed immediately and evaluated for all study measures),a hemin treated IR group (n=10) and a zinc protoporphyrin-Ⅸ (ZnPP-Ⅸ)treated IR group (n=8) that were fed with a high-fat diet.Rats with standardized chow diet were used as the normal control group (n=12). The rats in IR control group,hemin treated IR group and ZnPP-Ⅸ treated IR group were subsequently treated every other day with an intraperitoneal injection of normal saline,hemin (inducer of HO-1,30 μmol/kg) or ZnPP-Ⅸ (inhibitor of HO-1,10 μmol/kg) for 4 weeks.Rats in the normal control group remained on a standardized chow diet and were treated with intraperitoneal injections of normal saline every other day for 4 weeks.Systolic arterial blood pressure (SABP) was measured by tall-cuffed microphotoelectric plethysmography.The blood carbon monoxide (CO) was measured by blood gas analysis. The levels of nitric oxide (NO),inducible nitric oxide synthase (INOS),endothelial nitric oxide synthase (eNOS),blood glucose (BG),insulin,total cholesterol (TC) and triglyceride (TG) in serum,and the levels of total antioxidant capacity (rAOC),maIondialdehyde (MDA) and superoxide dismutase (SOD) in the aorta were measured.The expression of HO-1 mRNA and HO-1 protein in aortal tissue were detected by semi-quantitative RT-PCR and Western blot. The vasoreactive tensometry was performed with thoracic aortic rings (TARs).Results Compared with the normal control group,the levels of SABP,BG,insulin,TC,TG,NO,iNOS and MDA were higher.while the levels of CO,TAOC,SOD and eNOS were lower in IR control rats.After treatment of IR rats for 4 weeks a more intensive expression of HO-1 mRNA and HO-1 protein were observed in hemin treated IR group compared with the normal control group.And compared with 4-week IR control rats,the levels of CO,TAOC,SOD and eNOS were increased,while the levels of SABP and iNOS activity were lower in the hemin treated IR group.Administration of hemin in IR rats appeared to improve the disordered vasorelaxation of TARs to acetylcholine (ACh).Alternatively,the reverse results of SABP,CO,TAOC,SOD,iNOS and vasorelaxation responses to ACh were observed in IR rats with administration of ZnPP-Ⅸ.Conclusions The endothelial dysfunction in the aorta is present in the IR state.The protective effects of HO-1 against aortic endothelial dysfunction may be due to its antioxidation and regulative effect of vasoactive substances.It is proposed that hemin,inducer of HO-1,could be a potential therapeutic option for vascular dysfunction in IR states.关键词
heme oxygenase-1/hemin/insulin resistance/oxidative stressKey words
heme oxygenase-1/hemin/insulin resistance/oxidative stress分类
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..Hemin, a heme oxygenase-1 inducer, improves aortic endothelial dysfunction in insulin resistant rats[J].中华医学杂志（英文版）,2008,121(3):241-247,7.基金项目
This study was supported by the grants from the Natural Science Research Program of Guangdong Province(No.Z03038)and the Science Research Foundation of Guangdong Province(No.A2005448). （No.Z03038）
