Abdominal Wall Defects In Rats Research Articles

Peritoneal Regeneration Induced by an Acellular Bovine Pericardial Patch in the Repair of Abdominal Wall Defects

This study was to evaluate the feasibility of using an acellular bovine pericardium fixed with genipin (AGP) to repair an abdominal wall defect created in a rat model. The glutaraldehyde-fixed acellular pericardium (AGA), the genipin-fixed cellular pericardium (GP), and a commercially available polypropylene mesh were used as controls. Gross examination at 3-month post-operatively revealed that dense adhesions to the visceral organs were observed for the polypropylene mesh and the AGA patch, while a filmy to dense adhesion was seen for the GP patch. In contrast, no adhesion to the visceral organs was observed for the AGP patch. Histologically, inflammatory cells were found mainly surrounding the GP patch. In contrast, host cells (inflammatory cells, fibroblasts, and neo-capillaries) were able to infiltrate into the AGA and AGP patches. Unlike the AGA patch, the AGP patch retrieved at 1-month post-operatively became well integrated with the host tissue near the suture line. Additionally, there were some mesothelial cells, identified by the van Gieson stain, observed on the AGP patch. At 3-month post-operatively, a neo-peritoneum was observed on the AGP patch. The neo-peritoneum consisted of organized vascularized connective tissues covered by an intact layer of mesothelial cells. The calcium contents of the polypropylene mesh and the AGA patch increased significantly at 3-month post-operatively, while those of the GP and AGP patches stayed minimal throughout the entire course of the study. The results obtained in the study revealed that the AGP patch effectively repaired abdominal wall defects in rats and successfully prevented the formation of post-surgical abdominal adhesions.

Tissue Regenerating Capacity of Carbodiimide-Crosslinked Dermal Sheep Collagen during Repair of the Abdominal Wall

In future, the function of collagen-based biomaterials as temporary scaffolds for the generation of new tissue may be emphasized. In this study the function of dermal sheep collagen (DSC) crosslinked with carbodiimide (ENDSC) as repair material for abdominal wall defects in rats was compared with that of commercial hexamethylenediisocyanate-crosslinked HDSC. The results indicate that early after implantation both ENDSC and HDSC functioned well as a matrix for cellular ingrowth. However during further implantation HDSC soon degraded resulting in herniations, while ENDSC showed a delay in the degradation time of at least 20 weeks. ENDSC thereby enabled collagen new-formation and functioned as a guidance for muscle overgrowth. These results are very promising concerning the problem of the ongoing foreign body reaction with continuing risk of implant rejection observed in clinical practice with non-degradable materials.

Evaluation of absorbable polyglycolic acid mesh as a wound support

The ideal wound-support material would reinforce a wound early in the healing process when intrinsic wound strength is the weakest, yet disappear over time, preventing many of the untoward late effects seen with currently utilized nonabsorbable materials. This study was designed to evaluate the effectiveness of a newly designed absorbable material, polyglycolic acid mesh (Dexon), as a buttress for abdominal wounds closed under moderate tension. Young male rats (n = 211) were divided into three experimental groups. Animals in groups 1 (n = 96) and 2 (n = 95) had a 1.2 cm2 midline abdominal wall defect created and closely primarily. Animals in group 2 had a 2 X 5 cm piece of polyglycolic acid mesh sutured to the anterior abdominal wall overlying the closed abdominal defect. Animals in group 3 (n = 20) were unoperated controls. The animals in groups 1 and 2 were killed 1, 2, 3, 4, and 5 weeks after surgery. The entire anterior abdominal wall was removed and placed upon a bursting strength testing device. Bursting strength determinations of the supported and unsupported abdominal closures revealed that the strength of the wounds reinforced with polyglycolic acid mesh was significantly greater than unsupported wounds at 1, 2, and 3 weeks after surgery. Wounds supported with mesh had bursting strengths similar to unoperated abdomens by the first postoperative week. This study demonstrates that abdominal wall defects in rats closed primarily develop increased wound strength when the closure is supported by absorbable polyglycolic acid mesh. The use of an absorbable material may alleviate potential late complications associated with implantation of nonabsorbable materials. The clinical application of such a material remains to be determined.

Use of xenograft corium for reconstruction of abdominal wall defects

Corium autografts and corium zenografts prepared in Merthiolate prior to lyophilisation were used to repair surgically-created, full-thickness abdominal wall defects in rats. They were found to be equally effective in preventing the development of abdominal hernias.