| Background: Traumatic shock is a kind of common severe disorder after trauma. In recent 10 years, with the development of molecular biology, the pathogenesis of shock has been investigated on the level of molecule intensively. It is find that many cytokines and inflammatory medium participate in the processes of traumatic shock. But the therapy on shock, especially on severe shock is difficult, for traumatic shock is a complicated pathophysiologial process influenced by multiple factors, and the real mechanisms is unclear at present. In addition, there is no real effective measures to intervene and treat directly at its process.NO is an important vasoactive-substance. It is synthesized from L-arginine by a family of enzymes termed NO synthases (NOS). More and more researches show that NO plays a vital role in the pathophysiological processes of shock, and NO is an important mediator for pathophysiological alterations associated with loss of vascular reactivity, multiple organ dysfunction and even lethality. By now almost all researches have concentrated on the septic and hemorrhagic shock. There is few systematic research on the synthesis and role of NOS isoforms during traumatic shock.P-selectin is a kind of cell adhesion molecules. It plays important role in mediating leukocyte-endothelial interaction, immunologic rejection during organ transplantation, growing of tumor cells and vascularization. In recent years there are researches to show that P-selectin plays important role during infection, trauma, hemorrhage and shock. However, the alteration, distribution and degree of P-selectin in tissue during traumatic shock are unclear.ObjectiveThe animal model of traumatic shock in rat was made to investigate the dynamic changes of each forms of NOS activity in organs and mechanisms ofNO synthesis during traumatic shock. The NOS inhibitors and L-arginine were infused during resuscitation. The changes of NOS were detected and the survival time, the 24h survival rate were recorded, which would provide experimental foundation for the clinical application.2. In order to provide the new pathway for clinical therapy and to investigate the action and mechanisms of adhesion molecules during traumatic shock, the distribution, alteration and significance of P-selectin in vital organs and serum were determined.Methods and Results1. The dynamic changes of NOS activity in organs during traumatic shockA rat traumatic shock model was made by fracturing bilateral thighbone. 32 rats were randomly assigned to control group(n=8), 0.5h after shock group(n=8) and 3h after shock group(n=8) and 5h after shock group(n=8). The cNOS and iNOS activity of liver, spleen, lungs, small intestine and heart were measured during shock. We found in control rats cNOS activity was expressed in all organs and there was a small quantity iNOS expressed in lungs and liver; 0.5h after shock, cNOS was elevated in almost all organs to various degree and cNOS activity in liver and small intestine were significantly increased, but iNOS activity was not change. 3h after shock, an increase in iNOS activity and decrease in cNOS were observed, which was significantly compared with control group. 5h after shock, cNOS activity was still decreased significantly but iNOS activity was elevate in large range compared with 3h shock group. We also found that there was no effect on NOS activity in heart during shock.2. The study in therapy effect of NOS and L-arginine during traumatic shock32 rats were made traumatic shock model and were randomly assigned to control group(n=8), L-NAME group(n=8), AG group(n=8) and L-Arg group(n=8). During resuscitation, Ringer's solution, L-NAME (10mg/kg),AG (100mg/kg), L-Arg(100mg/kg) were infused to traumatic shock rats. 5h after shock, liver, spleen, small intestine, lung, heart were dissected, homogenated, and then the NOS activity was measured. The results showed that in L-NAME group the iNOS and cNOS activity were significantly decreased compared with control group. In AG group, cNOS activi...
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