A Study On The Expression Of VWF And VEGF In The Blunt Trauma Of Rat Muscle

Background and purpose: The estimation of time since injury is based on the plerosis responds of pathophysiology, which is the characteristic of vital reaction during the recovery of wound in different time section, including the character of morpholog and histochemistry and biochemistry changes of inflammation, granulation tissue, Epithelial proliferation and so on. These chatacteristics help forensic pathologists to evaluate the time since injury. The direct consequence of injury which usually cause damages to vascular endothelium are the chain reaction of blood coagulation, which takes place in the very first stage of hemostasis, then subsequently hyperemia ,edema and so on. von Willebrand Factor (vWF) plays a pivotal role in hemostasis , in which vWF contributes to both platelet adhesion/aggregation and bloodcoagulation through its multiple adhesive functions for the platelet membrane receptors, glycoprotein Ib-IX-V complex, integrin alphallbbeta3, heparin, various types of collagen, and coagulation factor VIII. Among various functions, the most characteristic feature of vWF is its determinant role on platelet thrombus formation under high-shear-rate conditions. Vascular endothelial growth factor (VEGF), which promotes mobilization of stem cells to the circulation, contributing to the formation of functional vasculature. VEGF interacts with its receptors, VEGFR₂ and VEGFR₁, expressed on endothelial and hematopoietic stem cells, and thereby promotes recruitment of these cells to neo-angiogenic sites, accelerating the revascularization process. In progress of tissue plerosis, the endogenetic growth factors play important role of regulation. All these make it possible to estimate the time since injury by check the immediately change of coagulation factors and growth factors.Methods: Sixty-five Spragwe-Dawley rats were randomly divided into injury, posthumous injury and normal group, each group has5 rats. The injury group was divided into 10 subsections as 15min, 30min, lh, 3h, 6h, 12h, Id, 3d, 5d, 7d according to the time when put rats to death. The posthumous injury group was divided into 30min and lh two subsections, we use immunohistochemistry method and image analysis meter to study the expression of vWF and VEGF in the muscle.Results: (l)at the early stage of injury the expression of vWF in small artery and small vein is different: vWF expression in the endothelium cellof small artery was descent fast immediately after injury, and begin to increase by Id after injury, and come back to normal level by 3d after injury; in the same time, vWF expression in the endothelium cell of small vein goes another way, it increase significantly in the early stage of injury, and decrease slowly since 3h after injury, and go back to normal level by 3d after injury, but in general, the signal level of vWF of muscle tissue decreased immediately after injury, and then slowly come back to normal level. (2)VEGF expression increased immediately after injury, and reach the peak value and keep at a high level by 7d.Conclusion: Both VEGF and vWF change in the early stage of injury: VEGF expression increases and vWF expression decreases, and vWF remains at low level for a short period, the application of VEGF and vWF could be objective indication of extimation of time since injury.