Calcium Hydroxide Increases Human Umbilical Cord Mesenchymal Stem Cells Expressions of Apoptotic Protease-Activating Factor-1, Caspase-3 and Caspase-9

PURPOSE: Calcium hydroxide is a gold standard dental material generally used for pulpal and periapical therapy including regenerative endodontic procedures because of its positive properties. However, evaluation about this material on stem cells is limited. Human umbilical cord mesenchymal stem cells (HUCMSCs) are potential to be used in regenerative therapy. Regenerative therapy needs a sustainable cell supply to maintain its regenerative capacity. The aim of this study was to ascertain the apoptosis result of calcium hydroxide on HUCMSCs through the expression of apoptotic protease-activating factor-1 (APAF-1), caspase-3, and caspase-9. MATERIALS AND METHODS: This study used a thawed frozen stock of passage 5 HUCMSCs, grown in minimum essential medium (MEM) alpha containing calcium hydroxide at concentration of 0.1 microgram/mL for 1, 3 and 7 days. Polyclonal antibody with fluorescence isothiocyanate (FITC) label was used to evaluate the expressions. APAF-1, caspase-3, and caspase-9 expressions were recorded and compared on every observation day using fluorescence microscope. Analysis of variance was performed to analyze the significance among the results of treatment groups. The results were concluded significant if p<0.05. RESULTS: The addition of calcium hydroxide in MEM alpha medium increases HUCMSCs expression of APAF-1, caspase-3 and caspase-9 significantly, compared to the control group without calcium hydroxide (p<0.05) in all the times. Day 1 showed the lowest increase followed by higher expressions on day 3 and day 7. CONCLUSION: HUCMSCs express increased APAF-1, caspase-3 and caspase-9 after in-vitro calcium hydroxide exposure. This should be considered when using calcium hydroxide on HUCMSCs for regenerative procedures with regard to other positive properties.