EFFECT OF LPS AND POLY: IC (TLR AGONISTS) ON NITRIC OXIDE PRODUCTION AND APOPTOSIS INCUBATION IN ACTIVATED T CELLS BY MOUSE MESENCHYMAL STEM CELLS (MSCS)

Mesenchymal stem cells (MSCs) were introduced as multipotent nonhematopoietic precursor adult cells. Pre or anti-inflammatory features of these cells appear on immune
responses by activating specific tool like receptors (TLRs). The aim of this study was to evaluate the
effect of Lipopolysaccharide and Polyribocytidylic Acid on different concentration and times of
incubation on nitric oxide production and apoptosis induction in activated T-cells.
Materials & Methods: Suspension cells were prepared through the femural and tibial bones by flushing
method; and Mesenchymal cells were isolated by plastic adhesion technique. When the cultures reached
% 70 confluence, cells treated with TLR agonists, Poly: IC (1 and 5 µg/ml), LPS (10 and 20 ng/ml) and
the lowest combination concentrations (Poly: IC 1µg/ml and LPS 10ng/ml) (LP) at two different times,
1 and 12hr. Nitric oxide of cell surface liquid were measured by Griess (year) method. Apoptosis
percentage in T cells was assayed by flowcytometry in the presence of Achridin orange/propidium
iodide (AO/PI).
Results: The results showed that Poly: IC could induce the highest T cells apoptosis at low concentration
(1 µg/ml) after 12hr incubation. But, LPS could cause T cells apoptosis at high concentration (20 ng/ml)
after 1hr incubation (P<0.05). Also, an increase in T cells apoptosis could be related to nitric oxide
production.
Conclusion: These findings suggest that the concentration of agonist and treatment period of the stem
cells could affect nitric oxide production and apoptotic activity in MSCs.