COLLAGEN SYNTHESIZED IN FLUOROCARBON POLYMER IMPLANT IN THE RABBIT CORNEA

The integration of microporous polymer into tissues is of great intere st for the production of keratoprosthetic devices. Our previous studie s showed functional differentiated cells and collagen synthesis in the pore of an expanded polytetrafluoroethylene implant. This study ident ifies and quantifies collagen types synthesized in the implant. Expand ed polytetrafluoroethylene polymers were implanted in the rabbit corne as. The collagen extracted from the polymer and implanted stroma after 1, 3 and 6 months was quantified by measuring hydroxyproline. The rel ative proportions of collagen types were determined by densitometric a nalysis after SDS-PAGE. The collagen-to-protein ratio in the polymer i ncreased from 0.22 to 0.70 between the first and third month after imp lantation becoming similar to control cornea. So that of the protein a nd collagen densities in the polymer and implanted stroma were similar to the control from the third month. The collagen synthesized in the polymer was mainly type I (87%) plus a small amount of type III (8%) 1 month after implantation. The collagen distribution from the third mo nth after implantation was similar to that of the controls and remaine d constant thereafter in the polymer implant and in the implanted stro ma. Immunogold labelling techniques confirmed these results. Implantat ion of this PTFE disc induced no obvious modification of the corneal s troma, confirming that this polymer is a good interface that is compat ible with the native corneal stroma. The keratocytes in this polymer r apidly adopted a corneal phenotype, distinct from the dermal or scarin g phenotype as shown by the collagen types produced in the implant. (C ) 1996 Academic Press Limited