Comparsion of Migration Pattern between Young and Senescent Mesenchymal Stem Cells in Time Lapse Microscopy

Abstract

Mesenchymal stem cells (MSCs) can differentiate into a variety of cell types, and thus are fundamental players in modern regenerative medicine. To maintain the viability and the potentials for self-renewal and multilineage differentiation of MSCs in vitro development remains a big challenge. Previous approaches found that when MSCs were cultured on chitosan membranes, they tended to aggregate and form a 3D spheroid; meanwhile, their differentiation efficiency was likely to improve. Cellular motility is an important index to reflect the viability and differentiation ability of stem cells during in vitro development. In order to investigate the variation of motility during this cell cultural environment, videos of cells were recorded for 72 hours by an ASTEC® CCM-1.4XZY/CO2 system with a CCD camera mounted on a time-lapse microscope with a magnification ratio of 100:1. We applied video tracking and image processing techniques to quantify cell mobility pattern in terms of moving speed and topological changes. Two types of MSCs, human adipose-derived adult stem cells (hADSCs) and human placenta derived multipotent cells (hPDMC), were investigated in this study. Each type contained two different passages: the 5th and 11th for hADSCs, and the 8th and 16th for hPDMC. The preliminary results from analysis of these 4 videos showed that the migration pattern of aggregated cellular spheroid in terms of moving speed and orientation consistency was significantly higher than those of single cells. In addition, young MSCs (with lower passage) were found to have a higher tendency to aggregate and form a spheroid than the senescent ones (with higher passage). This better spheroid-forming ability with young MSCs could result in their greater mobility than the senescent cells and thus yield their better capability in differentiation.