ABSTRACT
OBJECTIVE: To study the effects of bone marrow mesenchymal stem cell( BMSC) transplantation on early stage of inflammation in mice exposed to silica dust. METHODS: Specific pathogen free healthy male C57 BL /6 mice were used.Five mice were used to isolate BMSCs using bone marrow adherent method. Thirty mice were randomly divided into 3groups: control group,silica group and BMSCs transplantation group. The mice of the control group were given 20. 0 μL of0. 90% sodium chloride solution by one time intratracheal injection. The mice of silica group and the BMSCs transplantation group first received 20. 0 μL( 250 g / L mass concentration) of silicosis dust suspension by one time intratracheal injection; followed by 500. 0 μL of 0. 90% sodium chloride solution in the silica group,and 500. 0 μL of BMSCs suspension( cell density 1 × 109/ L) by tail vein infusion in the BMSCs transplantation group 6 hours later. Mice were euthanized on the 7th day of the experiments. The histopathology changes in lung tissues were examined. The serum levels of interleukin( IL)-1β, IL-6 and IL-10 were detected by enzyme linked immunosorbent assay. Real-time quantitative polymerase chain reaction was used to detect the mRNA relative expression levels of above cytokines in the lung tissues. RESULTS: The positive rates of BMSCs surface molecules cluster differentiation( CD) 29,CD34,CD90,CD105 and CD106 were 67. 70%,0. 12%,39. 00%,37. 10% and 20. 10%,respectively. Histopathology examination showed the thickened alveolar walls,broadening alveolar septum and the damaged alveolar structure in silica group. In the BMSCs transplantation group,there was no obvious damage found in the lung tissue. There was no change in the alveolar cavity and alveolar structure was complete. The IL-1β and IL-6 levels in serum and mRNA relative expression of IL-1β and IL-6in lung tissue in the silica group were higher than those of the control group and BMSCs transplantation group( P < 0. 05).The IL-1β level in serum and mRNA relative expression of IL-1β in lung tissue in the BMSCs group were higher than those of the control group( P < 0. 05). The IL-10 level in serum and mRNA relative expression of IL-10 in lung tissue in all groups showed no statistical difference( P > 0. 05). CONCLUSION: The BMSCs can alleviate pulmonary inflammatory damage at early stage by down-regulating the expression of proinflammatory factors of IL-1β and IL-6.
