Effect Of Acellular Bovine Pericardium Matrix Patch On Capsule Formation In Porcine

Part ? A preliminary study on acellular matrix patch of bovine pericardium in vivoObjective To establish an in vivo model of acellular bovine pericardium matrix patch using miniature pigs.To observe the fusion,vascularization and dissolution of acellular patch in vivo,and to measure the changes in main mechanical properties.Methods Bovine pericardium acellular matrix was implanted into miniature pigs for 1 month and 3 months.The gross morphology was observed and the shrinkage ratio of the specimens were measured.The tissue rejection,angiogenesis,intergration,and dissolution were assessed by H&E staining and Masson staining.The capsule formation,myofibroblast proliferation and cytokine expressions were evaluated by ?-SMA,VEGF and TGF-?1 immunohistochemistry staining.Changes in main mechanical properties were measured by strength tester.Results After the bovine pericardium acellular matrix patch was implanted,there was mild inflammatory reaction and no apparent fibrous capsule.The patch shrank significantly(1.99 ± 0.04cm2 vs 1.83 ± 0.05cm2,P <0.05)after 3 months and the thickness of the patch did not change.The internal collagen fibers were dissolved significantly after 3 months(0.693 ± 0.071 vs 0.821 ± 0.038,P <0.05).There was no significant myofibroblast proliferation or VEGF or TGF-?1 expression adjacent to the patch.The tensile strength and elongation at break were significantly decreased after 3 months(3.45±0.39 Mpa vs 1.77±0.31 Mpa,P<0.01;108.02±13.31N/cm vs 54.04±5.62N/cm,P<0.01;68.76±12.77% vs 11.12±2.34%,P<0.01).Conclusion Bovine pericardium acellular matrix material not only has great biocompatibility,vascularization and degradation ability,but also has a long stability.The biological patch could provide enough biomechanical properties in 3 months.Bovine pericardium acellular matrix material is a promising biological patch to meet the needs of breast reconstruction and plastic surgery.Part ? The animal studies on the effect of bovine pericardium acellular matrix patch on tissue expander capsule formationObjective To establish an animal model to study the effect of bovine pericardium acellular matrix patch on fibrous capsule formation induced by expander implantation.To investigate the potential application of acellular matrix patch in preventing capsule contracture.Methods Tissue expander alone(control group)or with bovine pericardium acellular matrix patch(experimental group)was implanted into bilateral sides of miniature pig abdomen.Samples were obtained at 1 month and 3 months(n=8 per group).H&E staining and Masson staining were performed to observe the capsule formation and the impact of patch on capsule formation.The myofibroblast proliferation and cytokine expressions were observed by ?-SMA,VEGF and TGF-?1 immunohistochemistry staining.Result After implantation of the biological patch,no apparent fibrous capsule or myofibroblast formation was observed in the coverage area.The capsule tissue was divided into compact layer and porosity layer.There was ?-SMA expression only in the compact layer,and significantly higher TGF-?1 expression in the compact layer than in the porosity layer.The capsule thickness and ?-SMA positive expression were not different in experimental group compared to control group.The capsule thickness in adjacent areas of the patch was significantly lower compared to that in distant areas of the patch,and the thickness of ?-SMA-positive area in the capsule had a similar trend.Angiogenesis was observed in the patch during capsule formation,and was more apparent in outer rim than in inner rim.Conclusion The bovine pericardial acellular matrix material has good biocompatibility and reduces the inflammatory response in the coverage area.By suppressing the proliferation of fibroblasts and myofibroblasts,the biological material inhibits the contractible capsule formation near the expander and decreases the capsule thickness of adjacent tissue.In summary,the bovine pericardial acellular matrix material is playing a vital role in slowing down the capsule contracture.