| Background:Hemorrhagic shock is a kind of complication caused by kinds of circulating blood volume decrease,such as trauma and blood loss.When hemorrhagic shock occurs,the body will produce a series of pathophysiological changes,such as decreased circulating blood volume and declined tissue perfusion,microcirculation disturbance,anaerobic metabolism,tissue acidosis,and even the development of Multiple Organ Dysfunction Syndrome and death due to the numerous blood loss.Fluid resuscitation is an effective measure to treat hemorrhagic shock.The main purpose of resuscitation is to expand the blood volume,maintain blood perfusion and improve tissue oxygenation.But the current resuscitation fluids have not the capacity of oxygen-carrying,though they can expand the blood volume.Hemoglobin based oxygen carrier,a kind of red blood cell substitutes,was used to treat hemorrhagic shock,which could reach the tissues that red blood cells can't achieve to maintain the tissue oxygenation owing to the smaller size.In this study,the oxygen-carrying plasma substitute was prepared by the junction of hemoglobin based oxygen carrier(polymerized placental hemoglobin)and hydroxyethyl starch.So it has both the capacity of oxygen-carrying and volume expansion.Previously study showed that the oxygen-carrying plasma substitute could increase the survival rate of rats and improve the microcirculation disorders.Therefore,in this study,we further investigated the effects of the oxygen-carrying plasma substitute after resuscitation in a severe hemorrhagic shock rat model with 60%blood loss.Objective:Volume-controlled hemorrhagic shock rat model with 60%blood loss was used in this study to investigate the effects of the oxygen-carrying plasma substitute after resuscitation on tissue oxygen pressure,blood perfusion,inflammation and the enzymatic and pathological changes of heart,liver and kidney organs.Methods:Male SD rats were subjected to severe hemorrhagic(60%loss of the total blood volume)and randomly divided into the oxygen-carrying plasma group,rat red blood cell group and hydroxyethyl starch group for the same volume of fluid resuscitation.The changes of blood pressure,heart rate and blood cell count were recorded and measured at baseline,shock,1h after resuscitation and 2h after resuscitation.At 2h after resuscitation.The liver,kidney,lung and intestine were incised to prepare 10%tissue homogenate by adding 9 times volume of cold saline for the measurement of MDA and MPO.And the level of TNF-a and IL-6 in intestine tissue was measured.The level of CK,LDH,AST,ALT,BUN and Cr in plasma were measured at baseline,shock,2h and 24h after resuscitation to evaluate the function of heart,liver and kidney.In addition,the changes of perfusion volume and tissue oxygen partial pressure were monitored at baseline,shock and 24h after resuscitation.At the end of study,the rats were sacrificed and the liver,kidney and heart tissues were quickly incised to fix using 10%formaldehyde for the measurement of histopathologic changes.Results:Experimental results showed that hemorrhagic shock caused declined blood pressure.The blood pressure and blood gases were partially restored after resuscitation fluids administration.MAP in oxygen-carrying plasma substitute group was higher than the other two groups.Lac in the oxygen-carrying plasma substitute group was decreased,tissue oxygen pressure and blood perfusion were improved compared with hydroxyethyl starch group.In addition,oxygen-carrying plasma substitute group significantly decreased the level of TNF-??IL-6?MPO activities.The level of CK and LDH in the oxygen-carrying plasma substitute group were higher than hydroxyethyl starch group and red blood cell group at 2h and 24h after resuscitation.The level of AST and ALT in the three groups were not increased significantly at 2h after resuscitation but increased significantly at 24 hours after resuscitation,the level of ALT in oxygen-carrying plasma substitute group was higher than the other two groups.The level of Cr in oxygen-carrying plasma substitute group was higher than the other two groups at 2h and 24h after resuscitation.After 24 hours of resuscitation,the oxygen partial pressure and perfusion were higher in the oxygen-carrying plasma substitute group than hydroxyethyl starch group.Pathological analysis showed that there are no changes of heart,kidney and liver in red blood cell group.Changes of kidney and liver were observed in the oxygen-carrying plasma substitute group and hydroxyethyl starch group.Heart lesion was also observed in the oxygen-carrying plasma substitute group.Conclusion:The oxygen-carrying plasma substitute both has the capacity of oxygen carrying and volume expansion,which could maintain a higher blood pressure and bring oxygen to issues to improve the tissue oxygenation and the state of acidosis.And it can maintain higher tissue perfusion and attenuate the activation of neutrophil and decrease intestine inflammatory response,but with some injuries of heart,kidney and liver at 24h after resuscitation. |
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