[Application of acellular dermal matrix loaded collagen binding domain-vascular endothelial growth factor patch in urethral wound repair in beagles].

To investigate the application value of acellular dermal matrix (ADM) loaded collagen binding domain-vascular endothelial growth factor (CBD-VEGF) patch in the repair of urethral wound in beagles. Twenty-one healthy adult beagles were selected to establish urethral wound model and randomly divided into 3 groups, which were treated with different repair methods. CBD-VEGF patch was prepared and instantaneous implantation was performed as the models were successfully built. The blank control group was treated without any repair materials;the ADM group was treated with collagen patch for repair and the ADM loaded with CBD-VEGF group was treated with collagen patch loaded with VEGF for repair. The safety and effectiveness of the three groups of materials implanted into the urethral wound model at 6 months after surgery were compared. Urodynamic examination, urethral angiography and pathological examination were used to evaluate the recovery of urethral tissue in the three groups. Compared with blank control group and ADM patch group, there was no complications or other adverse conditions in the ADM-loaded CBD-VEGF patch group. Urethrography was performed to measure the diameter of the urethra in the experimental segment, the mean urethral diameter of blank control group [(3.07±0.43) mm] was significantly smaller than that of ADM patch group [(3.73±0.11) mm] and ADM loaded CBD-VEGF patch group [(3.64±0.32) mm], with statistical difference (<0.05). Pathological examination with HE and Masson staining showed more proliferative blood vessels in the ADM loaded CBD-VEGF patch group. HE staining indicated that there were more proliferative vessels in the group of CBD-VEGF patch loaded with ADM. Masson staining showed that the positive area percentage of collagen tissue in the three groups was 34.27%±7.40%, 29.08%±3.79% and 28.02%±2.39%, respectively, with no statistical difference between the three groups(all >0.05). There was no excessive deposition of collagen tissue in the two groups using collagen patch. The percentage of positive staining per unit area in the three groups were 1.4%±0.1%,1.8%±0.1%3.1%±0.2%, respectively, and the difference was statistically significant among three groups and between every two groups (all <0.01), indicating the vascular density of CBD-VEGF group loaded with ADM was the highest. ADM loaded CBD-VEGF patch is a good biological support material for covering the wound after urethral surgery, and it provides an alternative direction for promoting the healing of the urethral wound.