Survival in a Rat Model of Lethal Hemorrhagic Shock Is Prolonged Following Resuscitation With a Small Volume of a Solution Containing a Drag-Reducing Polymer Derived From Aloe Vera

Abstract

Drag-reducing polymers (DRP) increase tissue perfusion at constant driving pressure. We sought to evaluate the effects of small-volume resuscitation with a solution containing a DRP in a rat model of hemorrhage. Anesthetized rats were hemorrhaged at a constant rate over 25 min. In protocol A, total blood loss was 2.45 mL/100 g, whereas in protocol B, total blood loss was 3.15 mL/100 g. Five minutes after hemorrhage, the animals were resuscitated with 7 mL/kg of either normal saline (NS) or NS containing 50 microg/mL of an aloe vera-derived DRP. In protocol B, a third group (CON) was not resuscitated. Whole-body O2 consumption (Vo2) and CO2 production (Vco2) were measured using indirect calorimetry. In protocol A, 5/10 rats in the NS group and 8/10 rats in the DRP group survived for 4 h (P = 0.14). Mean arterial pressure was higher in the DRP-treated group than in the NS-treated group 45 min after resuscitation (89 +/- 8 vs. 68 +/- 5 mmHg, respectively; P < 0.05). In protocol B, survival rates over 2 h in the DRP, NS, and CON groups were 5/15, 1/14, and 0/7, respectively (P < 0.05). Compared with NS-treated rats, those resuscitated with DRP achieved a higher peak Vo2 (9.0 +/- 1.0 vs. 6,3+/- 1.0 mL/kg/min) and Vco2 (9.0 +/- 1.1 vs. 6.0 +/- 1.0 mL/kg/min) after resuscitation. We conclude that resuscitation with a small volume of DRP prolongs survival in rats with lethal hemorrhagic shock.

Cell Distribution and Segregation Phenomena During Blood Flow

“…These studies were originally motivated by the knowledge that small amounts of long-chain polymer additives-"drag-reducing polymers" (DRPs) -can dramatically reduce drag in turbulent flows while having negligible effect on laminar flows [94]. Studies with laboratory animals indicate that the addition of DRPs to blood leads to many beneficial effects, including (1) reduced atherosclerotic plaque deposition ( Figure 11.3(a)) [90,95]; (2) increased cardiac output [96] and reduced severity of cardiac stenosis or myocardial infarction [97][98][99][100]; (3) improved survival probability after severe hemorrhage with use of polymer-containing resuscitation fluids [91,93,101] (see Fig. 11.3(b)); (4) reduced immune attack of implanted polymeric tissue scaffolds [92] (see Fig.…”

“…Experiments in microfluidic devices [93,105] have shown that the addition of a small amount of DRPs to suspension of RBCs results in a redistribution of RBCs with a significant reduction in the [90]. (b) Survival vs. time for rats subjected to hemorrhage and not treated (CON), treated by injection of normal saline (NS) or intravenously injected with saline containing a drag-reducing polymer [91]. (c) Poly(L-lactate) tissue scaffolds recovered after 7 weeks of implantation in a rat.…”

In vivo measurement of velocity profiles in arterioles

“…Attempts at explaining the mechanism of this effect by changes in blood rheology were not confirmed in experiments on viscosimeters [5][6][7], because numerous specific factors of functioning of a living microcirculatory bed (MCB) forming blood rheology could not be reproduced simultaneously [2]. The curve of velocity profiles reflects real value of shear rate in the stream, while its changes in the vessel indicate transformation of the bloodflow regimen and hence, qualitative changes in blood rheology.…”

“…The development of methods for adequate evaluation of blood rheology acquired special significance in studies of the effects of surface-active substances on blood supply intensity under critical conditions caused by acute blood loss (hemorrhagic shock) [2,[5][6][7]. Attempts at explaining the mechanism of this effect by changes in blood rheology were not confirmed in experiments on viscosimeters [5][6][7], because numerous specific factors of functioning of a living microcirculatory bed (MCB) forming blood rheology could not be reproduced simultaneously [2].…”

Possible Prophylaxes of Aloe Vera Juice with CoQ10 to Enhance Muscle Performance

“…Marcias CA. group concluded that resuscitation with a small volume of DRP prolongs survival in rats with lethal hemorrhagic shock [11] . Sixteen adult male rats were anaesthetized and mechanically ventilated.…”