To observe and study the process of peritoneal regeneration induced by basement membrane biologic mesh in rats with partial level defects in the abdominal wall via intraperitoneal onlay mesh (IPOM).

Twenty-one healthy rats were selected for the model construction of partial-level defects of the abdominal wall. After modeling, three rats were used as a control group to observe the modeling effect. Eighteen rats were repaired with 4-layer and 12-layer basement membrane biologic mesh, 9 rats in each group. At 2, 3 and 4 weeks postoperatively, three rats were killed to obtain and observe the repair area and its surrounding tissues. The peritoneal reconstruction and tissue repair process in early stage were evaluated by gross observation, histopathological staining, neovascularization labeling, and immunofluorescence labeling of mesothelial cells.

Gross observation and neovascularization labeling two weeks after implantation showed that basement membrane biologic mesh could promote tissue vascularization. The neovascularization spread from the pore of mesh to the surrounding areas as blood supply. HE and Masson staining demonstrated significant tissue regeneration on the ventral wall side and peritoneal side of the mesh, with new tissue spreading peripherally from the mesh, and gradually cover and wrap the mesh. Immunofluorescence labeling of mesothelial cells demonstrated the formation of a flat, continuous layer of mesothelial cells on the surface of the new tissue on the peritoneal side, that is peritoneal regeneration.

During IPOM abdominal wall repair, the basement membrane biologic mesh can guide tissue regeneration and peritoneal reconstruction at an early stage. The new tissue spreads from the abdominal wall side to the abdominal cavity side through the mesh pores. Tissue layer and a continuous mesothelial cell layer was formed on the surface of the biologic mesh, effectively preventing the occurrence of adhesion of the mesh to the internal organs.