Experimental Study Of Platelet-rich Fibrin In Skin Graft On Bone Exposed Wound

Research purposesOur group investigated the effects of autologous platelet-rich fibrin on the survival of subdermal vascular network grafts to explore platelet-rich fibrin.The auxiliary skin graft was used to treat the bone exposure,the survival of the graft skin,and the healing of the exposed wounds.It was verified whether PRF could promote the regeneration of surrounding soft tissue.Research methodPlatelet-rich fibrin preparation:20 ml of blood was collected from the heart,3000 rpm,and centrifuged for 10 minutes.The middle layer gel was dehydrated and used.In the experimental group,the rabbits were fixed in the prone position after anesthesia,and the proximal cranial bone bulge was bounded.The long and wide rectangular area of 4 cm x 2 cm was marked.The skin was cut along the marking line for use,and the subcutaneous tissue was removed more than the tissue to expose the skull.The platelet-rich fibrin film was trimmed to accommodate the size of the bony exposed,the skin was sutured in situ,and the pressure bandage was packaged.The treatment of the control group was the same as that of the experimental group,and no PRF was added.The wound healing of each group was observed at 3 days,7 days and 10 days after operation.The survival of the skin was recorded.The skin tissue was cut out by each group.The number of neovascularization and inflammation were observed by HE staining and immunofluorescence staining.The microvessel density and skin survival rate of the experimental group and the control group were compared.Experimental results1.Skin growth and survival rateOn the third day after operation,the growth of the control group was poor.On the 7th day after surgery,the growth of the control group was worse than that of the experimental group.On the 10th day after surgery,the growth of the control group was worse than that of the experimental group.The average survival rate of the skin graft in the experimental group was 91.73%,and the average survival rate of the skin graft in the control group was 83.51%.(P=0.045 P<0.05)There was a difference in the survival rate between the two groups.The survival rate of the skin in the experimental group was higher than that in the control group 10 days after surgery.2.H.E staining resultsIn the experimental group for 3 days,small blood vessels in the skin were dilated and hemorrhagic.Occasionally,epithelial cells formed small blood vessels,the number was small,the wall was thin,the red blood cells were connotated,the medium amount of inflammatory cells infiltrated,and a small amount of fibroblasts proliferated.In the control group for 3 days,the epidermis of the skin peeled off,the whole layer scattered in the inflammatory cells infiltration,the dermis was shallow,deep,and small blood vessels dilated and hemorrhage,occasionally new small blood vessels and fibroblasts.In the experimental group,7 days,under the epidermis,shallow dermis,deep in the proliferation of neovascular small blood vessels and fibroblasts,scattered in the distribution of inflammatory cells,the amount is small.In the control group for 7 days,the epidermis was shedding and necrosis,and a small amount of inflammatory cells in the superficial dermis were scattered,and some cells were degenerated,and occasionally scattered in the new blood vessels.In the experimental group for 10 days,the subepidermal and superficial dermis,deep small blood vessels and endothelial cells proliferated actively,and fibroblasts proliferated actively.Occasionally,neutrophils are scattered between tissues,and there is no bleeding in the interstitium.In the control group for 10 days,proliferating small blood vessels and proliferating fibroblasts were seen in the superficial dermis,and a small amount of inflammatory cells reacted.3.Immunofluorescence staining resultsIn the experimental group and the control group,the expression of VEGF increased with time in the 3rd,7th,and 10th days,especially in 7 days.Compared with the control group,CD34 and CD34 in the control group showed an increasing decreasing trend,and the peak was maintained at about 7 days.The statistical expression of VEGF fluorescence in each time group was statistically significant(P=0.049 P<0.05),and the experimental group was higher than the control group..4.Platelet-rich fibrin morphologyWhen the magnification is more than 4000,the surface fibrin is abundant,the shape is regular and clear,and the cross-section is interlaced,forming a dense and porous three-dimensional network structure.The fibrin trigeminal structure(three-molecular structure)can be seen everywhere,from the surface to the inside,the net The structure is getting denser and denser.Platelets scattered around the cluster can be seen in the fibrin network.Occasionally,red blood cells are scattered and attached to the surface of fibrin.Analysis conclusion1.Skin survival rateThe average survival rate of skin grafts in the experimental group was 91.73%,and the average survival rate of skin grafts in the control group was 83.5 1%(P=0.045 P<0.05).The survival rate of the skin grafts in the experimental group was higher than that in the control group 10 days after surgery.Platelet-rich fibrin can increase the survival rate of the skin.2.Neovascular densityThere was a statistically significant difference in the expression of VEGF between the experimental group and the control group(P=0.049 P<0.05).Platelet-rich fibrin promoted microvascular regeneration in the grafted skin.3.Histological performanceUnder the microscope,the experimental group had a lighter inflammatory reaction than the control group,and the new capillaries and fibroblasts proliferated significantly.4.Clinical applicationPlatelet-rich fibrin is effective in treating bone-exposed wounds after lower extremity trauma,and has a positive effect on accelerating tissue regeneration and promoting wound healing.