Dynamic behaviour of human bone marrow derived-mesenchymal stem cells on uniaxial cyclical stretched substrate - A preliminary study

Abstract

Tissues and cells in the body are continuously exposed tocomplex mechanical microenvironment forces. It is well known that mechanical stimulations are important to induce morphological changes, developments and, regeneration. Although the regulation of progenitor cells through mechanical induction has been previously described, the effects of uniaxial strain on monolayer MSC constructs have not been widely discussed. In this study, we investigated the effects of mechanical stretching on the alignmentand proliferation of human bone marrow mesenchymal stem cells (hMSCs) on elastomeric substratesin vitro. Two groups (mechanically loaded and static) were used in this study. hMSCs from human bone marrow were isolated and cultured. MSCs were passaged to P2/P3 before being seeded on elastomeric surfaces and allowed to settle for 72 hours before subjected to continuous cyclic uniaxial stretching (6% strain, 1 Hz). A specially designed stretch device capable of operating inside an incubator was used for this study.Image analyses were performed at 0, 6, 12, 24, 36 and 48 hours. Cell proliferation at various time points of mechanical loading was investigated using alamarBlue® assay. The results demonstrate that cells subjected to tensile loading are realigned inperpendicular to the unaxial stretching direction. The proportion of cell proliferation within the tensile loading group is higher than those in the control group. In conclusion, the results of this study suggest that MSCs are mechanosensitive,influencing cell proliferation and cell realignment. The knowledge that MSCs response to mechanical signals provides better understanding ofthe mechanical regulation involved in stem cells behaviourthus, allowing better control of cell growth. © 2011 Springer-Verlag.