Basic Control of Reperfusion Effectively Protects Against Reperfusion Injury in a Realistic Rodent Model of Acute Limb Ischemia

Abstract

Background-Reperfusion injury is insufficiently addressed in current clinical management of acute limb ischemia.Controlled reperfusion carries an enormous clinical potential and was tested in a new reality-driven rodent model. Methods and Results-Acute hind-limb ischemia was induced in Wistar rats and maintained for 4 hours. Unlike previous tourniquets models, femoral vessels were surgically prepared to facilitate controlled reperfusion and to prevent venous stasis. Rats were randomized into an experimental group (nϭ7), in which limbs were selectively perfused with a cooled isotone heparin solution at a limited flow rate before blood flow was restored, and a conventional group (nϭ7; uncontrolled blood reperfusion). Rats were killed 4 hours after blood reperfusion. Nonischemic limbs served as controls. Ischemia/reperfusion injury was significant in both groups; total wet-to-dry ratio was 159Ϯ44% of normal (Pϭ0.016), whereas muscle viability and contraction force were reduced to 65Ϯ13% (Pϭ0.016) and 45Ϯ34% (Pϭ0.045), respectively. Controlled reperfusion, however, attenuated reperfusion injury significantly. Tissue edema was less pronounced (132Ϯ16% versus 185Ϯ42%; Pϭ0.011) and muscle viability (74Ϯ11% versus 57Ϯ9%; Pϭ0.004) and contraction force (68Ϯ40% versus 26Ϯ7%; Pϭ0.045) were better preserved than after uncontrolled reperfusion. Moreover, subsequent blood circulation as assessed by laser Doppler recovered completely after controlled reperfusion but stayed durably impaired after uncontrolled reperfusion (Pϭ0.027). Conclusions-Reperfusion

Hypothermic, Initially Oxygen-Free, Controlled Limb Reperfusion for Acute Limb Ischemia

“…Positive effects of an oxygen-free perfusate were recently published in a rodent model of ALI. 25 In addition, we added allopurinol to the perfusate because it is known to inhibit the enzyme xanthin oxidase which is predominantly involved in the production of oxygen-free radicals. 23,30,32 Because hypothermia has been described to reduce postreperfusion skeletal muscle edema and to diminish IR injury, 22,24,36 we perfused at 22 C. The perfusion pressure was adjusted to values below 70 mm Hg, as suggested by others.…”

“…22,24 Recently, an improved rodent model of ALI indicated positive effects of a flow-controlled hypothermic (15 C) limb perfusion with a crystalloid solution for 20 min. 25 We have, therefore, established an initially oxygen-free, mildly hypothermic, heparin-coated extracorporeal membrane oxygenation (ECMO) and hemofiltration system. In this study, we report our experience with this perfusion technique.…”

Morphological illustration of alterations in the arterial endothelium in ischemic and reperfusion injuries

“…______________________________________________________________________________ Реперфузионный синдром является неизбежным явлением при восстановлении кровотока после продолжительной ише-мии [1,2]. Врачи специализированных от-делений вынуждены сталкиваться с ише-мией конечности и, как следствие, разви-тием повреждающей реоксигенации при успешно выполненной реканализации [3,4]. Происходит необратимая клеточная гибель ткани.…”

Refinement of tourniquet-induced peripheral ischemia/reperfusion injury in rats: comparison of 2 h vs 24 h reperfusion

“…For the induction of unilateral hind limb ischemia, approximately 30 min after induction of anesthesia, the femoral artery and vein were exposed via a groin incision, and a tourniquet (standardized weight of 450 g) was placed underneath the femoral vessels to block collateral circulation. 11 The femoral artery was occluded for 3 h with two microvascular clamps (B1-V; S&T, Neuhausen, Switzerland) ( Figure 1b). The rat hind limbs were not exsanguinated, but a comparable state was achieved by allowing venous return during the entire period of ischemia in order to prevent venous congestion and additional injury through microcirculatory impairment, which would not represent the clinical situation.…”