Host response after reconstruction of abdominal wall defects with porcine dermal collagen in a rat model

Objective The purpose of this study was to compare the inflammatory response after implantation of Pelvicol™ with Prolene™ in a rat model. Study design Full-thickness abdominal wall defects were created in 64 Wistar rats, and reconstructed with either Pelvicol™ or Prolene™. Animals were sacrificed on days 7, 14, 30, and 90 to evaluate the presence of herniation, infection, adhesions, and changes in thickness and tensile strength of the implants. Histopathology and immunohistochemistry were performed to evaluate the collagen deposition and the inflammatory response. Statistics were done with unpaired t test and Mann-Whitney rank test. Results Pelvicol implantation induced infiltration of granulocytes, macrophages, and NK cells, which showed up-regulated expression of surface activation markers ICAM-1 and CD11b. This inflammatory response was significantly milder, and declined faster than in Prolene-implanted rats, and was also associated with fewer adhesions. Moreover, Pelvicol induced a slower, but more orderly collagen deposition, paralleling the surface of the implant. Pelvicol implants showed a slower increase in thickness and tensile strength early on, but this difference disappeared by day 90. Conclusion Pelvicol induces a milder inflammatory response, less adhesion formation, more orderly collagen deposition than Prolene, and reaches a comparable tensile strength only after 90 days.