Experimental Study Of Human Acellular Dermal Matrix In The Repair Of Abdominal Wall Defects In Rabbits

Objective:By studying the effect of human acellular dermal matrix(HADM)in rabbit abdominal wall defect model,we explore the feasibility of human acellular dermal matrix to repair abdominal wall defects,which provides the basis of acellular dermal matrix to repair abdominal wall defects.Methods: 1.36 New Zealand white rabbits aged 2-3 months were selected to establish a rabbit abdominal wall defect wound model(subcutaneous tissue,muscle tissue and peritoneum were removed,full-thickness skin of abdominal wall tissue was retained),and they were randomly divided into two groups: experimental group(HADM+ full-thickness skin group)and control group(full-thickness skin group).2.Rabbits in each group were treated in different way: HADM+ fullthickness skin repair scheme was adopted in the experimental group,after forming a rabbit abdominal wall defect model,HADM mesh was used to repair the rabbit abdominal wall defect wound,and the basement membrane surface of the mesh was oriented to the intestinal tube,and then the full-thickness skin was sutured.In the control group,the rabbit abdominal wall defect model was made,and the defect was closed by simple suture of the preserved full-thickness skin.The rabbits at 4 weeks,8 weeks,16 weeks after surgery gotten air injection executedin each group,Six rabbits were killed at a time,before these rabbits to be put to death,we observed the general condition of abdominal incision and gross condition of each rabbit,recordedthe observations,and obtained the operation area of the abdominal wall for every group of animals,finally,the specimens were placed into 10% neutral formalin solution bags,and histological observation(HE staining and Masson trichrome staining)was performed.3.Jenkins Scale and Badylak scale were used for scoring,and the obtained data were statistically analyzed to evaluate the repair status of each group.Results:1.The experimental models of abdominal wall defects in both groups were successful.2.Gross observation results: in the experimental group,the implanted ADM and the surrounding abdominal wall were bonded well at 4 weeks,and some dense scar tissue was seen in the surrounding abdominal wall.At 8 weeks after operation,the implanted ADM and the surrounding abdominal wall showed annular contraction due to scar.At 16 weeks after operation,ADM implanted in the experimental group was integrated with the surrounding abdominal wall,the boundary was blurred,and the dense scar tissue was relatively flat and soft.In the control group,the dense scar tissue on the abdominal wall surface was obviously hyperplasia and clumped in the abdominal operation area at 4 weeks after operation,and a large amount of dense scar tissue with irregular shape was observed on the abdominal wall surface at 8 weeks after operation.At 16 weeks after operation,a large area of dense scar tissue on the abdominal wall surface was observed in the abdominal operation area,with a relatively hard texture.In the experimental group,at 16 weeks after operation,one animal(grade 3)had severe adhesion of ADM and intraperitoneal organs,and the others’ ADM and mesentery had only slight adhesion.In the control group,one animal(grade 2)had moderate adhesion in the abdominal wall and mesentery at 8 weeks and 16 weeks after operation,while the other animals only had slight adhesion.There was no significant difference in the degree of intraperitoneal adhesion between the two groups(Z=-0.087,P=0.930).The histological score of Badyla proprotein deposition in the experimental group was better than that in the control group at each time period(P < 0.05).3.Histological observation results: At the fourth week,there was more lymphocyte infiltration at the suture margin between ADM and normal abdominal wall tissue in the experimental group,and extensive neovascularization was shown on ADM.At 8 weeks,ADM fibroblasts in the experimental group also increased significantly,and a small number of new smooth muscle cells were found,and collagen deposition was found around muscle fibers.Good fibroblast growth was seen on the ADM tissue at 16 weeks,and more new smooth muscle cells were seen forming and were well aligned.In the control group,a small amount of collagen fibers formed at 4 weeks,and gradually increased and arranged disordered at 8 and 16 weeks,and no new muscle fibers were found.Conclusion:ADM may provide a crawling scaffold for rabbit abdominal wall smooth muscle cells,or may effectively repair abdominal wall defects by inducing proliferation and regeneration of rabbit abdominal wall smooth muscle cells,which may provide a new and more effective method for clinical repair of abdominal wall defects.