ADHESIVENESS OF HUMAN LIGAMENT FIBROBLASTS TO LAMININ

The adhesiveness of fibroblasts from the human anterior cruciate and m edial collateral ligaments to the laminin molecule was studied, with p articular emphasis on the intrinsic differences between fibroblasts fr om the two ligaments. Cellular adhesion strength, adhesion area, lamin in concentration, and seeding time were examined. Cell adhesion to lam inin anchored with poly-D-lysine to a cleaned cover glass was measured with a micropipette micromanipulation system after seeding. The adhes ion strength of fibroblasts from the anterior cruciate Ligament to lam inin was greater than and significantly different from that of fibrobl asts from the medial collateral ligament, depending on the laminin con centration. Fibroblasts from the anterior cruciate ligament also exhib ited an increase in adhesion strength, dependent on laminin concentrat ion of as much as 30 mu g/ml, at which the laminin receptors were thou ght to be saturated. Fibroblasts from the medial collateral ligament d id not show such an increase except at laminin concentrations of 5-10 mu g/ml. There was no significant difference in adhesion area between fibroblasts from the two ligaments except after 45 minutes at a lamini n concentration of 40 mu g/ml. For both, the adhesion to laminin showe d little correlation to seeding time during periods of as long as 60 m inutes. Measurements of adhesion area also failed to show a significan t correlation to seeding time for fibroblasts from either ligament at laminin concentrations of 20 and 40 mu g/ml. Adhesion strength normali zed by adhesion area had no correlation to seeding time. With all time s taken into account, however, normalized adhesion strength for fibrob lasts from the anterior cruciate ligament was approximately two times greater than and significantly different from that for fibroblasts fro m the medial collateral ligament at laminin concentrations of 20 and 4 0 mu g/ml. Fibroblasts from the anterior cruciate ligament adhere more strongly to laminin than do those from the medial collateral ligament . This study may prove useful in the understanding of fibroblast adhes ion to the basal lamina within the extracellular matrix and may provid e insight into the natural healing processes of the anterior cruciate and medial collateral ligaments.