| Objective:To investigate the role of monocyte chemoattractant protein -1 and its receptor CCR2 axis in MSCs homing after myocardial infarction, and to explore the mechanisms and methods of improving treatment outcome.Methods:1, chemotaxis assays in vitro The third passage of MSCs were divided into three groups, MSCs without treatment, MSCs with hypoxic preconditioning and MSCs treated by rabbit anti-CCR2 neutralizing antibody. The different groups of MSCs were placed in the upper tier of Transwell plate. The chemokine of MCP-1 (200ng/ml) was added at the bottom of the plate. The migration number of different groups of MSCs was accounted. 2, MCP-1 expression levels were detected by immuno-histochemical at different time points ( 1, 3 , 7, 14, 28 d ) after myocardial infarction in different areas ( infarct center, infarct border zone and normal myocardial area ). 3, Twenty swines were randomly divided into four groups. They received MSCs transplantation one week after MI. Group A was control group. Group B was conducted with MSCs transplantation. Group C received transplantation of MSCs with hypoxic preconditioning. Group D was transplanted with rabbit anti-CCR2 neutralizing antibody-treated MSCs. 4, Myocardial infarction model was established by gelatin sponge embolization. Different groups of MSCs (1×107 / 5 mL) were injected transcatheterly into the remote embolization of LAD. Four weeks later, hemodynamics were used to assess the heart function. The change of each index of cadiac function was detected by Powerlab + Millar pressure catheter and UCG. Heart histological test was done four weeks after stem cell transplantation.Vessel number was counted by immuno- histochemisty staining with anti Factor-Ⅷantibody. The number of MSCs homing was detected by Brdu labeled. Results: 1, The migration ratio of MSCs with HPC was the highest (P <0.05). MSCs without treatment could migrate, but significantly weaker than the group of MSCs with HPC (P <0.05), while MSCs treated by rabbit anti-CCR2 neutralizing antibody had no significant migration effect (P <0.05). 2, In the MI central area, MCP-1 expression began to increase at the first day, reached the peak at the 3d and then decreased to normal levels after two weeks. In the MI border zone, it began to increase during the 1d, reached the highest in one week, and then gradually decreased normal level after four weeks. One week after MI MCP-1 expression was the highest in the infarct border zone. 3, The swines received MSCs transplantation one week after MI. Left ventricular function and angiogenesis density and the number of MSCs homing by Brdu labeled were detected four weeks after MSCs transplantation. Group C was significant better than other groups (P <0.05). Meanwhile, group D was better than group A (P <0.05).Conclusion: 1, MCP-1/CCR2 axis was involved in MSCs homing. 2, MSCs with hypoxic preconditioning would increase the surface receptor expression of CCR2. 3, The tissue had MCP-1 after MI. The infarct border zone had the highest expression of MCP-1 one week after MI. 4, The increase of MSCs homing with hypoxic preconditioning could significantly improve heart function. 5, Transplantion of MSCs treated by rabbit anti-CCR2 neutralizing antibody could improve left ventricular function and angiogenesis density. It showed that not only MCP-1/CCR2 axis took part in MSCs homing,but also other axises did. |
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