生脉注射液对肠粘膜再灌注损伤保护作用机制的实验研究

目的探讨生脉注射液(SM)对休克再灌注期间肠粘膜的保护作用及机制.方法利用兔休克复苏模型,21只家兔随机分为SM组(A组)、单纯复苏组(B组)和对照组组(C组).分别于实验前(S0)、休克1h(S1)、及再灌注1h(R1)、3h(R3)观察乙状结肠粘膜内pH(pHi)、肠氧摄取率(ERO2)、肠粘膜一氧化氮(NO)、丙二醛(MDA)及钙(Ca2+)含量、肠粘膜病理病理形态学变化.结果A组R1和R3时肠pHi及肠ERO2明显高于B组相应值,肠粘膜NO、MDA及Ca2+含量低于B组(均为P＜0.05),而B组复苏期间肠pHi维持在S1时的低水平状态,肠ERO2显著降低,肠粘膜NO、MDA及Ca2+含量均明显高于A组和C组;光镜下肠粘膜损伤A组显著轻于B组且病理分级与肠pHi负相关(r=-0.841,P＜0.05).结论SM对休克再灌注期间肠粘膜的保护作用机制为增加肠粘膜灌注及氧合、抑制肠粘膜NO活性、清除氧自由基及减轻钙超载.

Mechanism of protective effect of Shengmai injection on intestinal mucosa during hemorrhagic shock in rabbits

Objective Shengmai injection (SM) is a preparation of traditional Chinese herbal medicine with tonic action and has been effectively used in the treatment of different types of shock. The purpose of this study was to explore the mechanism of its protective effect on intestinal mucosa during shock in rabbits. Methods 21 healthy rabbits of both sexes weighing 2.0-2.5 kg were anesthetized with pentobarbital sodium 30 μg@ kg-1 and fentanyl 10 μg@ kg-1 iv. The animals were tracheotomised and intubated and mechanically ventilated. PET CO2 was maintained between 4.687-5.33 kPa. Left femoral artery was cannulated for measurement of BP, blood withdrawal and blood sampling. A catheter was inserted into portal vein for portal vein blood gas analysis. Tonometer probe was placed in sigmoid colon for measurement of pHi. Hemorrhagic shock was induced by blood withdrawal from femoral artery at a rate of 2ml@ kg-1 @ min -1 until MAP dropped to 5.33 kPa. MAP was maintained at this level for 60 min then the collected blood was returned to the animal. The rabbits were divided into 3 groups of 7 animals each: group A: hemorrhagic shock was induced and maintained for 60 min. SM 2.1 ml@ kg -1 was diluted and slowly infused with the returned blood; group B: hemorrhagic shock was induced and maintained for 60 min as in group A but no SM was given. group C: sham operation without shock. Intestinal pH (pHi) and intestinal ERO2 were measured before shock (S0), 1 h after shock(S1 ), 1 h (R1) and 3 h (R3) after collected blood was returned. A segment of ileum (6 cm) was removed at R3 and NO, MDA and Ca2+ contents of intestinal mucosa were measured. Intestinal mucosa damage was graded by microscopic examination.Results pHi and intestinal ERO2 were higher in group A than those in group B at R1 and R3. NO, MDA and Ca2+ contents of intestinal mucosa in group B were significantly higher than those in group A and C.Intestinal mucosal damage was slight in group A as compared with that in group B. There was a good negative correlation between pHi and intestinal mucosa damage ( r = - 0.841, P ＜ 0.05 ). Conclusions The results show that SM can protect intestinal mucosa from ischemia-reperfusion injury during hemorrhagic shock through improving perfusion and oxygenation, inhibiting the activities of NO and reducing oxygen free radicals and calcium overload.