Effects of bone marrow-derived mesenchymal stem cells on mRNA and protein expression of toll like receptor of rat alveolus macrophages / 中华创伤杂志

ABSTRACT

ObjectiveTo investigate the effect of bone marrow-derived mesenchymal stem cells (MSCs) on gene and protein expression of toll-like receptor, TLR2/4 of the rat alveolus macrophages so as to discuss the effect of MSCs transplantation on the early inflammatory mediators and the regulatory mechanism of the inflammatory cascade.MethodsThe alveolus macrophages were randomly divided into the PBS control group (n = 24), MSCs control group (n = 24), lipopolysaccharide (LPS) control group (n=24) and LPS + MSCs treatment group (n =24).All groups were taken time-points of 1, 3,6, 12 hours.Positive cell rate of MSCs with surface mark and the expression level of TLR2/4 protein on macrophage were detected by flow cytometry.The mRNA level of TLR2/4 expression on macrophage was detected by RT-PCR and the concentrations of TNF-o in cell culture supernatants by ELISA at the different time points.ResultsCompared with the PBS control group and MSCs control group, TLR2/4 mRNA and protein levels were significantly up-regulated, markedly increased at one hour and peaked at 12 hours (P ＜0.01) and the TNF-α concentrations in cell culture supernatants were significantly up-regulated and peaked at 6 hours in the LPS control group (P ＜ 0.01).Compared with the LPS control group, mRNA and protein level of TLR2/4 and TNF-o concentrations in the cell culture supernatants of the LPS + MSCs group were markedly down-regulated (P ＜ 0.01).ConclusionsWith LPS stimulation, TLR2/4 mRNA and protein expressions as well as TNF-αt concentration increase, when the peak of the TNF-αt concentration appears slightly earlier, indicating that there may be a positive feedback loop between TLR2/4 expression and TNF-ot.MSCs can significantly reduce TLR2/4 mRNA and protein expressions as well as TNF-α concentration after LPS stimulation, indicating that MSCs can break up the positive feedback loop.