ADHERENCE, PROLIFERATION AND COLLAGEN TURNOVER BY HUMAN FIBROBLASTS SEEDED INTO DIFFERENT TYPES OF COLLAGEN SPONGES

We describe an in vitro model that we have used to evaluate dermal sub stitutes and to obtain data on cell proliferation, the rate of degrada tion of the dermal equivalent, contractibility and de novo synthesis o f collagen. We tested three classes of collagenous materials: (1) reco nstituted non-crosslinked collagen, (2) reconstituted collagen that wa s chemically crosslinked with either glutaraldehyde, aluminium alginat e or acetate, and (3) native collagen fibres, with or without other ex tracellular matrix molecules (elastin hydrolysate, hyaluronic acid or fibronectin). The non-crosslinked reconstituted collagen was degraded rapidly by human fibroblasts. The chemically crosslinked materials pro ved to be cytotoxic. Native collagen fibres were stable. In the absenc e of ascorbic acid, the addition of elastin hydrolysate to this type o f matrix reduced the rate of collagen degradation. Both elastin hydrol ysate and fibronectin partially prevented fibroblast-mediated contract ion. Hyaluronic acid was only slightly effective in reducing the colla gen degradation rate and more fibroblast-mediated contraction of the m aterial was found than for the native collagen fibres with elastin hyd rolysate and fibronectin. In the presence of ascorbate, collagen synth esis was enhanced in the native collagen matrix without additions and in the material containing elastin hydrolysate, but not in the materia l with hyaluronic acid. These results are indicative of the suitabilit y of tissue substitutes for in vivo application.