RESULTS: In vitro, cultured MDSC spontaneously differentiated into insulin-expressing islet-like cell clusters as revealed using MDSC from transgenic mice expressing GFP or mCherry under the control of an insulin promoter. Differentiated clusters of beta-like cells co-expressed insulin with the transcription factors Pdx1, Nkx2.2, Nkx6.1, and MafA, and secreted significant levels of insulin in response to glucose challenges. In vivo, undifferentiated MDSC injected into streptozotocin (STZ)-treated mice engrafted within 48 h specifically to damaged pancreatic islets and were shown to differentiate and express insulin 10-12 days after injection. In addition, injection of MDSC into hyperglycemic diabetic mice reduced their blood glucose levels for 2-4 weeks.

Methods: This study was carried out at the Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia, between June 2016 and July 2017. Bone marrow cells were isolated from nine mice and cultured in a growth medium. Various concentrations of NAC between 0.125-2 μM were added to the culture for 48 hours; these cells were then compared to non-supplemented cells harvested from the remaining three mice as the control group. A trypan blue exclusion test was performed to determine cell viability, while intracellular ROS levels and genotoxicity were determined by hydroethidine staining and comet assay, respectively. The lineage commitment potential of erythroid, myeloid and pre-B-lymphoid progenitor cells was evaluated via colony-forming cell assay.

Results: NAC supplementation at 0.25, 0.5 and 2 μM significantly increased cell viability (P <0.050), while intracellular ROS levels significantly decreased at 0.25 and 0.5 μM (P <0.050). Moreover, DNA damage was significantly reduced at all NAC concentrations (P <0.050). Finally, the potential lineage commitment of the cells was not significantly affected by NAC supplementation (P >0.050).