胸部硬膜外神经阻滞对高脂血症家兔冠状动脉粥样硬化形成的影响

Protective effect of thoracic epidural anesthesia against coronary atherogenesis in cholesterol-fed rabbits

目的 探讨胸部硬膜外神经阻滞 (TEA)对实验性高脂血症家兔冠状动脉粥样硬化形成的影响。方法 健康纯种新西兰雄兔 2 1只 ,随机分为三组 ,每组 7只。对照组 :普通饲料喂养 ;高脂组 :普通饲料 +1 5g胆固醇 /d ;TEA组 :普通饲料 +1 5g胆固醇 /d +TEA(0 12 5 %布比卡因 0 3ml,2次/日 )。实验前和实验第 2、4、6、8周分别从耳中央动脉抽血 2ml,测定血清中总胆固醇 (TC)、甘油三脂(TG)、高密度脂蛋白 (HDL C)、低密度脂蛋白 (LDL C)的水平 ,实验第 8周末 ,气栓法处死全部动物 ,立即开胸取出心脏 ,固定后在心室乳头肌水平横断心室 ,切片染色后 ,用BHEC显微微机图象处理系统测定横断面每根肌间小动脉截面的硬化程度。结果 实验前三组血清血脂水平无显著性差异 (P >0 0 5 ) ;与对照组比较 ,高脂组及TEA组血清TC、TG、LDL C水平显著升高 (P <0 0 5或 0 0 1) ,但高脂组与TEA组比较 ,各阶段均无显著性差异 (P >0 0 5 ) ;三组血清HDL C水平无显著性差异 (P >0 0 5 )。肌间小动脉粥样硬化发生率 (IA) ,内膜增厚发生率 (IT) ,病变面积与总面积 (内膜面积 +管腔面积 )之比及内膜面积与总面积之比 ,TEA组均明显低于高脂组 (P <0 0 1) ,而管腔面积与总面积之比 ,TEA组明显高于高脂组 (P <0 0 1)。

Objective To study the antiatherogenic effects of thoracic epidural anesthesia (TEA) in cholesterol fed rabbits Methods Twenty one New Zealand white rabbits were randomly allocated to receiving either normal diet (control group,n=7) or normal diet plus cholesterol 1 5g/day (hypercholesterol group,n=7), or normal diet plus cholesterol 1 5g/day and TEA with 0 125% bupivicaine 0 3ml twice a day (TEA group, n=7) The serum levels of total cholesterol (TC), triglyceride (TG),high density lipoprotein cholesterol(HDL C) and low density lipoprotein cholesterol (LDL C) were measured before and 2,4,6 and 8 weeks during experiment At the end of the 8th week,all rabbits were killed by air embolism Heart was removed and kept in 10% formalin for a week The ventricles were transversely sectioned at the level of papillary muscle and slices from the cross section of the ventricles were obtained for determination of the degree of atherosclerosis by computer image analysis system Results Blood lipid levels were similar among the three groups before the experiment (P>0 05) TC,TG, and LDL C levels were markedly higher in hypercholesterol group and TEA group during the experiment than those in control group(P<0 05 or 0 01), but there was no difference between hypercholesterol group and TEA group (P>0 05) There was no significant difference in HDL C among the three groups (P>0 05) The incidences of atherogenesis and intimal thickening and the ratio of the atherosclerotic area to total area (intimal area plus intraluminal area) and the ratio of intimal area to total area , were remarkably lower inTEA group than those in hypercholesterol group(P<0 01),however the ratio of intraluminal area to total area was obviously higher in TEA group than that in hypercholesterol group(P<0 01) Conclusions TEA can inhibit the development of atherogenesis to a great extent in cholesterol fed rabbits, indicating that the cardiac sympathicotonia plays an important role in coronary atherogenesis