Search

Differentiation of bone marrow mesenchymal stem cells (BMSCs) into neural cells has received significant attention in recent years. However, there is still no practical method to evaluate differentiation process non-invasively and practically. The cellular quality evaluation method is still limited to conventional techniques, which are based on extracting genes or proteins from the cells. These techniques are invasive, costly, time consuming, and should be performed by relevant experts in equipped laboratories. Moreover, they cannot anticipate the future status of cells. Recently, cell morphology has been introduced as a feasible way of monitoring cell behavior because of its relationship with cell proliferation, functions and differentiation. In this study, rat BMSCs were induced to differentiate into neurons. Subsequently, phase contrast images of cells taken at certain intervals were subjected to a series of image processing steps and cell morphology features were calculated. In order to validate the viability of applying image-based approaches for estimating the quality of differentiation process, neural-specific markers were measured experimentally throughout the induction. The strong correlation between quantitative imaging metrics and experimental outcomes revealed the capability of the proposed approach as an auxiliary method of assessing cell behavior during differentiation.

Abstract Human mesenchymal stem cells (hMSCs) are capable of self-renewal and differentiation into various cell lineages. Mechanical stimuli have been shown to regulate function of stem cells through alteration in morphology and structure. The aim of this study was to evaluate and compare effects of uniaxial static stretch and combined static-dynamic stretch on the orientation, regulation and cytoskeletal structure of hMSCs. Mean values of topological were calculated before and after loadings. Moreover, fractal dimension (FD) was employed to quantify alterations in shape complexity of the cells. Internal cytoskeletal structure of cells was observed by actin filament staining. Results demonstrated a statistically significant change in cell topology and FD due to 10% static-dynamic stretch after 24 h. Static stretch was not as influential as dynamic loading. Whereas for combined static-dynamic stretch systemic alignment of cells was detected, in the static test group local alignment of actin fibers was observed, although the entire cell network was not totally aligned in a specific direction. It was concluded that dynamic stretch leads to cytoskeletal alignment and repolarization of hMSCs, whereas static stretch does not. Under static stretch hMSCs proliferated more than under dynamic stretch. Results can be applied in tissue engineering when functionalization of stem cells is required.