A New Experimental Model for the Evaluation of Wound Healing: Porous Polyethylene Implantation

ABSTRACT

Tissue regeneration, such as neovascularization and collagen synthesis, is the most important element throughout the whole process of wound healing. However, this research lacks an appropriate experimental model for the quantitative analysis of the extent of tissue regeneration that takes place in the animal experiments. This lack motivated us to introduce our experimental model, using Medpor(R)(porous polyethylene implant). Our model is designed to analyze the degree of tissue regeneration quantitatively on the basis of the which concept of "the amount of tissue ingrown during a definite time period within a definite volume unit." After medpor discs were loaded with fibroblast, they were implanted at the back of 2 white rats. In control group the medpor discs were not load with cells. Six discs per group(total 12 discs) were used in this study. At three time intervals from 1 to 3 weeks, the implanted discs were harvested and processed for histologic study. The microvascular density method(MVD) was adopted to observe neovascularization, of which only obvious microvessels were counted under the light microscopy(x 100), while the focus of the microscope was fixed at the center of the sample unit segmented. Following the 1st, 2nd and 3rd week observation periods, the noticeable change was identified in the ingrowths of soft tissues of both control and fibroblast group. Regarding MVD, there was no significant difference among groups at 1 and 2 weeks. At 3 weeks, there was significant difference in MVD between the 2 groups; the MVD of fibroblast group(26 and 34) was markedly higher than that of the control group(14 and 16). It is expected that the our experimental model will have a wide application to the whole of research concerned with processes of wound healing involving angiogenesis, regeneration experimentation, etc.