Effect Of Adherent Molecule In Vascular Avulsion Injury

Skin avulsion injury is the most commonly encountered trauma in Plastic Surgeon's daily work. It was proved that micro-vessels thrombosis could induce secondary necrosis of avulsed skin. The mechanisms of intravascular thrombosis of avulsed tissue have not been fully clarified.In this study, we tried to explore effects of avulsion injury on endothelium and relationship between traction force and vascular occlusive rate in a rat vascular injury model. Different extent traction forces were applied to femoral artery and vein of rats for different time course. With light microscopy and scanning electron microscope, we observed the changes of vascular endothelium, adherence of leukocyte and thrombosis.The characteristic venous endothelium changes are: I : Eminence.6.of endothelial cell, II : Scattered detachment of endothelial cell, HI: Extensive detachment of endothelial cell. The degree of endothelium injury was correlated with the extent of traction force. The extent of endothelium injury differed in different site. The most extensive injury occurred in the central of injury site and lessened at the peripheral.The characteristic arterial endothelium changes are: I : Rupture of endothelial cell, II : Valve-like change of endothelium. With the increase of traction force, endothelium changes trended to become type II.Furthermore, we explored the expression of CD lib, E-Selectin and P-Selectin of avulsed vessels via immunohistochemistry and RT-PCR. With light microscopy, we observed leucocyte adherenting to endothelium and leucocyte infiltrating under endothelium. We could observe leucocyte inside thrombus on arterial wall. A monoclonal antibody (mAb) specific for CDllb was used for the targeting of leucocyte, the result proved that leucocyte participated leucocyte-endothelial adherent and interaction.RT-PCR showed the expression of E-Selectin was positive correlated with the extent of traction force. The higher the force, the more extensive density could be observed in agarose gel electrophoresis. Immunohistochemistry showed that E-Selectin was.7.positively expressed on endothelial cells at injury site. Those results indicated that E-Selectin correlated with vascular injury. P-Selectin was expressed quickly after injury, and reached the peak about the 12th hour post-injury, and decreased at the 24th hour post-injury. The expression of P-Selectin was also positive correlated with the extent of traction force. Immunohistochemistry showed that P-Selectin was positively expressed on endothelial cells at injury site and platelet in thrombus. Those results indicated that P-Selectin participated in endothelial injury, platelet accumulation and thrombosis.The results indicated that by monitoring changes of Selectin level of patients after avulsion injury, we could predict the prognosis clinically. We also could apply mAb of Selectin or the analog of Selectin receptor (e.g. fucoidin) for the treatment of avulsion injury in the future.