The effect of cobalt (II) chloride in the viability percentage and the induced hypoxia inducible factor - 1 of human adipose mesenchymal stem cells (HAMSCs): An in vitro study

Introduction: The preconditioning of HAMSCs using Cobalt (II) Chloride (CoCl₂) as a hypoxia mimicking agent (HMA) may provide the adaptive state of HAMSCs. Objective: To examine the effect o<f CoCl2 in the viability percentage and the induced Hypoxia Inducible Factor-1a (HIF-1a) expression of HAMSCs in vitro. Methods: HAMSCs were thawed, cultured, and then sub-cultured from the laboratory cell stock. The Immunocytochemistry (ICC) methods with Fluorescein isothiocyanate (FITC) antibody labelling kit was used to validate the HAMSCs employing its Cluster of Differentiation (CD) expression such as CD73(+), CD105(+) and CD45(-). HAMSCs were sub-cultured and then co-cultivated with or without CoCl2 in the different concentration (200μmol, 150μmol, 100μmol, 75μmol, 50μmol, 25μmol) for 24 hours. The cytotoxicity test was conducted by utilizing tetrazolium dye MTT 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The formazan crystal was then observed, and the cell viability percentage was calculated. In examining CoCl2 induced hypoxia in HAMSCs, the expression of HIF-1a applied ICC-FITC in vitro. Analysis of Variance (ANOVA) was performed to analyze the obtained data statistically (p<0.05). Results: HAMSCs express CD73 and C105 positively, while HAMSCs expressed CD45 negatively. There is no significant different in cell viability percentage of HAMCs between groups with different concentrations of CoCl2 (p=0.99; p>0.05). CoCl₂ successfully induces the hypoxia confirmed by HIF-1a positive expression of HAMSCs after 24 hours incubation in vitro. Conclusion: CoCl₂ does not affect the viability percentage of HAMSCs and it can be used as a biocompatible HMA in HAMSCs in vitro.