Effect of HTK on the microcirculation in the rat cremaster muscle during warm ischemia and reperfusion

Abstract

Histidine-tryptophan-ketoglutarate (HTK) preserves rat muscle function during cold storage. We examined the effect of HTK perfusion on preservation of microvascular function during 4 h of warm ischemia and subsequent reperfusion (I/R) in the rat cremaster muscle. Leukocyte-endothelium interactions, capillary perfusion, and arteriole diameters were quantified prior to HTK-perfusion and/or ischemia, and at 0, 1, and 2 h after restoration of blood flow. In all groups, the number of rolling leukocytes increased with time, whereas I/R induced a slight increase in leukocyte adhesion. After ischemia, capillary perfusion rapidly recovered to about 50% and returned to near normal (90%) after 2 h. HTK at 22 degrees C did not affect the assessed microcirculation variables, whereas HTK at 4 degrees C reduced leukocyte rolling, but not adhesion. Therefore, microvascular function of HTK-perfused muscles was not better preserved during warm I/R than that of nonperfused muscles. Contrary to other preservation solutions, HTK perfusion in itself was not detrimental to the microcirculation.

Do Preservation Solutions Protect Rat Cremaster Microcirculation during Ischemia and Reperfusion?

“…For antioxidants to become effective, the reperfusion period should include a reflow period, in which oxygen enters the tissue and free radicals are formed. In the present study, as well as in a previous study [6], we demonstrated that, after a period of 4 h of total normothermic ischemia, capillary perfusion resumed at 50% of preischemic baseline levels right at the start of reperfusion. Within the subsequent 2 h reperfusion period this parameter recovered almost completely to baseline levels.…”

“…Previously, we studied the effects of 10 min of preischemic perfusion with HTK on the microvascular consequences of 4 and 6 h of ischemia [6]. HTK did not influence the (transient) decrease in tissue perfusion observed after ischemia and reperfusion.…”

“…The number of adhering leukocytes remained stable as well (0.89 Ϯ 0.11 during baseline and 0.94 Ϯ 0.22 after 6 h). Perfusion with HTK without ischemia resulted in a threefold increase in the number of rolling leukocytes compared to baseline and had no effect on the number of adhering leukocytes [6].…”

“…This group was used to determine the effects of Celsior per se, without ischemia, 4, 5, 6, 7, and 8 h after Celsior perfusion. Effects of HTK per se have been studied previously [6].…”

“…We hypothesized that preischemic perfusion with HTK, resulting in removal of blood cells from the microvasculature prior to ischemia and exposure of the microvasculature to HTK during ischemia, would reduce the adverse microvascular effects of ischemia and reperfusion. However, preischemic perfusion of the cremaster muscle with HTK did not change tissue perfusion after 4 and 6 h of warm ischemia and reperfusion, although a decrease in leukocyte endothelium interactions during reperfusion was observed [6]. The protective effects of Celsior in this situation, if any, are unknown.…”