Erythrocytes Inhibit Ligament Fibroblast Proliferation in a Collagen Scaffold

In this work, we hypothesized that the concentration of erythrocytes in a provisional scaffold would have a significant effect on three of the major biological processes occurring in early wound healing. ACL fibroblast proliferation, collagen production, and scaffold contraction were measured in collagen gels containing fibroblasts and erythrocytes in subphysiologic (1 x 10(8) erythrocytes/ml), physiologic (1 x 10(9) erythrocytes/ml), and supraphysiologic (1 x 10(10) erythrocytes/ml) concentrations. Fibroblast-seeded gels containing only platelet-poor plasma were used as a control group. All gels were cultured for 1, 14, and 21 days. DNA, ELISA for procollagen and scaffold size measurements were used to quantify the three above parameters of wound healing. Samples with concentrations of erythryocytes lower than that in whole blood stimulated greater fibroblast proliferation and scaffold contraction than those with erythrocyte concentrations similar to that in whole blood (p < 0.027; p < 0.03). Increasing the erythrocyte concentration over that in the whole blood stimulated fibroblast collagen production (p < 0.009) and limited scaffold contraction (p < 0.031). Further work examining the role of the erythrocyte in the early provisional scaffold is warranted. (C) 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1361-1366, 2011