Krysztopik R J, Bentley F R, Spain D A, Wilson M A, Garrison R N
Department of Surgery, University of Louisville, Kentucky, USA.
Br J Surg. 1997 Dec;84(12):1717-21.
Intestinal mucosal hypoperfusion and loss of barrier function during sepsis may contribute to maintaining the septic state. Free radicals are produced during sepsis and antioxidants improve survival from experimental sepsis. It is unclear whether endothelial cell injury from free radicals results in altered microvascular reactivity. Lazaroids are antioxidants which scavenge radicals and block lipid radical chain reactions. The authors sought to determine whether lazaroids altered the intestinal microvascular responses to sepsis.
In vivo video microscopy was used to study the ileal microcirculation of the rat. A1 (inflow) arteriolar diameter and flow, A3 (premucosal) arteriolar diameters, and cardiac output were measured. Lazaroid or vehicle was infused before a bolus injection of live Escherichia coli or saline.
Lazaroid alone had no effect on the intestinal vessels or haemodynamics. E. coli caused vasoconstriction (A1, -21 per cent, A3, -19 per cent of baseline) and hypoperfusion (-36 per cent) despite increased cardiac output (+31 per cent). Lazaroid significantly attenuated both constriction (A1, -11 per cent; A3, 10 to -1 per cent) and hypoperfusion (-15 per cent), but did not increase cardiac output (30 per cent).
E. coli bacteraemia led to intestinal vasoconstriction and hypoperfusion. Lazaroid reduced this effect without altering central haemodynamic responses, suggesting that free radicals have a deleterious effect on the intestinal microcirculation during bacteraemia.
脓毒症期间肠道黏膜灌注不足和屏障功能丧失可能有助于维持脓毒症状态。脓毒症期间会产生自由基，抗氧化剂可提高实验性脓毒症的存活率。尚不清楚自由基引起的内皮细胞损伤是否会导致微血管反应性改变。拉扎罗类药物是一种抗氧化剂，可清除自由基并阻断脂质自由基链反应。作者试图确定拉扎罗类药物是否会改变肠道微血管对脓毒症的反应。
采用体内视频显微镜研究大鼠回肠微循环。测量A1（流入）小动脉直径和血流量、A3（黏膜前）小动脉直径以及心输出量。在推注活的大肠杆菌或生理盐水之前输注拉扎罗类药物或赋形剂。
单独使用拉扎罗类药物对肠道血管或血流动力学没有影响。尽管心输出量增加了31%，但大肠杆菌仍导致血管收缩（A1，-21%；A3，-19%基线）和灌注不足（-36%）。拉扎罗类药物显著减轻了收缩（A1，-11%；A3，10%至-1%）和灌注不足（-15%），但并未增加心输出量（30%）。
大肠杆菌血症导致肠道血管收缩和灌注不足。拉扎罗类药物可减轻这种效应，而不改变中心血流动力学反应，这表明自由基在菌血症期间对肠道微循环具有有害作用。
