Article
A new polytrauma model of the mouse as combination of weight-drop injury of the brain and femur fracture plus hemorrhagic shock
Vorstellung eines neuen Polytrauma-Modells der Maus als Kombination eines geschlossenen Schädel-Hirn-Traumas, Femurfraktur und Schock
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Published: | April 11, 2007 |
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Objective: Fracture of the extremities with blood loss is a prevalent finding in one-third of patients with closed head injury. Nevertheless, there is no previous described mouse model simulating this serious clinical problem. Such a model is needed for better understanding of the complex systemic response to a polytrauma. Furthermore, the evaluation of suspected drugs, which may diminish the secondary damage has to be performed in experimental settings.
Methods: 20 male C57BL mices with a mean weight of 22g were anesthetized with ketamine and xylazine. The anaesthetized animals were first subjected to a standardized weight drop injury over the left parieto-temporal cortex. After preformance of a fracture of the left femur using a guillotine, a hemorrhagic shock by blood aspiration was induced. In the control groups either a weight drop injury of the brain only (n=20) or fracture of femur plus hemorrhagic shock (n=20) were performed.
The animals were sacrified at 96 hours following trauma or rather polytrauma. Intracardial blood sample was taken before. For further histopathological evaluation following organs were preserved: brain, lung, splen, kidney and liver.
Results: The mortality rate before the 96 hours was 45%. In the control groups there was no mortality. The inflammatory response measured by Il-6, TNFa, CD4+ and CD8+ cells was significantly stronger in the polytrauma group, in comparison with the control groups (p<0.01). The histopathological investigations of the brain (H&E, Nissl, GFAP) and peripheral organs (H&E) prove that the combination of the traumas generate a more severe damage than the addition of the singular components.
Conclusions: The findings of this study suggest that a combination of single trauma components can be used in a standardized manner to simulate the clinical problem. The effects caused by this combination are significantly more severe than the addition of the singular components.