Effect Of Bone Marrow Mesenchymal Stem Cells On Activation And Function Of Mouse Peritoneal Macrophages

Objective To explore the influence of bone marrow mesenchymal stem cells (MSCs)on macrophage activation after lipopolysarchride stimulation.Methods BALB/c mouse bone marrow MSCs were generated using general method,mice were injected intraperitoneally with 1 ml of 4%sterile Brewer TG medium 4 days prior to harvest of the macrophages by peritoneal lavage.TG-elicited macrophages were prepared as the plastic tissue culture plate-adherent population of cells from peritoneal exudates lavage rued essentially,nonadherent cells were removed by gentle washing,and the remaining adherent cells were cultured for experiment.The co-culture system was established by planting macrophages on the MSCs monolayer.The supematants were collected for TNF-α/TGF-βand NO assay after stimulating macrophages with LPS for about 18 hours.At the same time Escbericbia coli standard strain(ATCC25922)was added into the culture system and incubated for another 24 hours,macrophages were stained and the changes of phagocytosis were examined.Results There was small amount of cytokines in the supernatants in which macrophages were cultured alone without stimulating by LPS,and the concentration of TNF-αand NO increased significantly in the supematant to about(147.41±37.13) pg/ml and(59.93±8.74)uM after macrophages were activated;however,at the present of MSCs,the concentration of TNF-αdecreased dramatically after stimulation [(97.58±30.26)pg/ml,P=0.032],and the concentration of NO decreased gently [(50.90±29.48)uM,P＞0.05];interestingly,the concentration of TNF-αand NO decreased further after addition of the MSCs culture supernatants into the culture system[(58.28±31.54)pg/ml,(-3.36±2.31)uM P＜0.0005)].However,there was no statistical difference between each of the groups about the TGF-β(P＞0.05),MSCs had no effect on the phagocytic rate and phagoindex of macrophages after activation.Conclusions The results reveal for the first time that MSCs can inhabit the activation of mouse peritoneal macrophages after stimulating with LPS but without influence on the phagocytosis in vitro.