Novel method for the quantitative assessment of cell migration: A study onthe motility of rabbit anterior cruciate (ACL) and medial collateral ligament (MCL) cells

A novel method of quantitating cell migration has been proposed for the pot ential utilization of tissue engineered scaffolds. Applying Alt's conservat ion law to describe the motion of first passage ACL and MCL cells, we have developed a quantitative method to assess innate differences in the motilit y of cells from these two ligamentous tissues. In this study, first passage ACL and MCL cells were cultured from four mature New Zealand white rabbits . One side of the cell monolayer was scraped completely away to create a wo und model. The cell moved into the cell-free area, and cell density profile s were analyzed at 6 h and 12 h. Values of the random motility coefficient (mu) were then estimated by curve fitting the 6 h and 12 h data to a mathem atical model, derived from the conservation law of cell flux. During 6 h of incubation in medium supplemented with 1% FBS, MCL cells (mu(MCL) = 4.63 /- 0.65 x 10(-6) mm(2)/sec) were significantly (p < 0.05) more mobile than ACL cells (mu(ACL) = 2.51 +/- 0.31 x 10(-6) mm2/sec). At 12 h, the MCL cell s also appeared to move faster (mu(ACL) = 4.39 +/- 0.63 x 10(-6) mm(2)/sec, mu(MCL) = 6.59 +/- 1.47 x 10(-6) mm(2)/sec), but the difference was not st atistically significant (p = 0.18). Exposure of the cells to growth factors PDGF-BB or bFGF for 6 h had no significant effect on the migration of the ACL and MCL cells. However, exposure of the ACL cells (p < 0.05) and the MC L cells (p = 0.19) to 1 ng/mL of PDGF-BB for 12 h enhanced their migration. Incubation with a high concentration (100 ng/mL) of PDGF-BB or bFGF at con centrations tested (1 or 100 ng/mL) for 12 h, produced little or no migrato ry stimulation on these ligament cells. Our findings support the previous q ualitative observations made by numerous investigators. The novel methodolo gy developed in this study may provide a basis for tissue engineering, and the results may be applied to tissue reconstruction techniques of the knee ligaments.