Bahman Mansouri Motlagh - Department of Microbiology, Veterinary Faculty, Urmia University, Urmia, Iran
Nahideh Afzale Ahangaran - Department of Microbiology, Veterinary Faculty, Urmia University, Urmia, Iran
Seyyed Meysam Abtahi Froushani - Department of Microbiology, Veterinary Faculty, Urmia University, Urmia, Iran

Objective(s):Some evidence showed that calcitriol has an important role in regulating growth and differentiation of mesenchymal stem cells (MSCs). However, the interaction between mesenchymal stem cells and macrophage is not clear yet.  The current study was done to investigate the in vitro effects of calcitriol on the interactions between bone marrow-derived MSCs and rat macrophages. Materials and Methods: MSCs were isolated from rat bone marrow and pulsed with different concentrations of calcitriol (۵۰, ۱۰۰ and ۲۰۰ nanomolar) for ۲۴, ۴۸ and ۷۲ hr. Then, mesenchymal stem cells were co-cultured with macrophages for ۴ hr. Finally, macrophages were evaluated for ability to uptake neutral red, phagocytosis activity against opsonized yeast, respiratory burst and viability.  Results: Our data showed that bonemarrow-derived MSCs pulsed with calcitriol may cause a significant increase in uptake of neutral red and phagocytic activity of opsonized heat killed baker's yeast. Moreover, treatment of MSCs with calcitriol enhanced macrophage viability. Nevertheless, the respiratory burst of macrophages was significantly reduced in macrophages co-cultured with calcitriol-treated MSCs compared to control group. Conclusion: Calcitriol may accelerate and potentiate anti-inflammatory M۲ macrophage polarization by MSCs

Calcitriol, Macrophage, Mesenchymal stem cell