摘要
Background Erythropoietin （EPO） and granulocyte colony-stimulating factor （G-CSF） are both potential novel therapeutics for use after myocardial infarction （MI）.However,their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial.Therefore,we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarction rats and explored the potential mechanisms.Methods Four groups of rats were used：control （saline injection after MI,i.h.）,EPO （a single dose of 5 000 IU/kg after MI,i.h.）,G-CSF （a dose of 50 μg· kg-1· d-1 for 5 days after MI,i.h.）,and both EPO and G-CSF （EPO＋G-CSF,using the same regiment as above）.Cardiac function was assessed by echocardiography before and 1 day,7 days,14 days and 21 days after MI.CD34＋/Flk-1＋ cells in the peripheral blood were evaluated by flow cytometry before and 3 days,5 days and 7 days after MI.The infarct area and angiogenesis in the peri-infarct area were analyzed.The mRNA and protein expression of vascular endothelial growth factor （VEGF） and stromal-derived factor-1α （SDF-1α） in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting.Results Compared with the control and monotherapy groups,the EPO＋G-CSF group had significantly increased CD34＋/ Flk-1＋ endothelial progenitor calls （EPCs）in the peripheral blood （P ＜0.05）,up-regulated VEGF and SDF-1α levels in the peri-infarct region （P ＜0.05）,enhanced capillary density （P ＜0.05）,reduced infarct size （P ＜0.05） and improved cardiac structure and function （P ＜0.05）.G-CSF alone did not dramatically increase EPCs in the peripheral blood,enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group.Conclusions Combined treatment with EPO and G-CSF increased EPCs mobilization,up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment,subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size.All factors contributed to its beneficial effects on cardiac function in post-infarction rats.
Background Erythropoietin （EPO） and granulocyte colony-stimulating factor （G-CSF） are both potential novel therapeutics for use after myocardial infarction （MI）.However,their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial.Therefore,we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarction rats and explored the potential mechanisms.Methods Four groups of rats were used：control （saline injection after MI,i.h.）,EPO （a single dose of 5 000 IU/kg after MI,i.h.）,G-CSF （a dose of 50 μg· kg-1· d-1 for 5 days after MI,i.h.）,and both EPO and G-CSF （EPO＋G-CSF,using the same regiment as above）.Cardiac function was assessed by echocardiography before and 1 day,7 days,14 days and 21 days after MI.CD34＋/Flk-1＋ cells in the peripheral blood were evaluated by flow cytometry before and 3 days,5 days and 7 days after MI.The infarct area and angiogenesis in the peri-infarct area were analyzed.The mRNA and protein expression of vascular endothelial growth factor （VEGF） and stromal-derived factor-1α （SDF-1α） in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting.Results Compared with the control and monotherapy groups,the EPO＋G-CSF group had significantly increased CD34＋/ Flk-1＋ endothelial progenitor calls （EPCs）in the peripheral blood （P ＜0.05）,up-regulated VEGF and SDF-1α levels in the peri-infarct region （P ＜0.05）,enhanced capillary density （P ＜0.05）,reduced infarct size （P ＜0.05） and improved cardiac structure and function （P ＜0.05）.G-CSF alone did not dramatically increase EPCs in the peripheral blood,enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group.Conclusions Combined treatment with EPO and G-CSF increased EPCs mobilization,up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment,subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size.All factors contributed to its beneficial effects on cardiac function in post-infarction rats.
基金
This work was supported m part by the National Natural Science Foundation of China （No. 81100071, 81371632, 81270252 and 81070160）, the Heilongjiang Province Foundation for Returness （No. LC08C36）, the Heilongjinang Province Outstanding Youth Foundation （No. JC201208）, the Collegiate Changjiang Scholar Reserve Support Plan of Heilongjiang Province （No. 2013 CJHB001）, the National Basic Research Program of China （973 program） （No. 2014CB542401）, and the Natural Science Foundation of Heilongjiang Province （No. D201121, GC09C408-2） Conflicts of interest： none.Acknowledgments： Part of the work was carried out in the Department of Cardiovascular Medicine in Nippon Medical School and presented in the 20th World Congress of the ISHR 2010 in Kyoto. Authors thank Drs. Gen Takagi and Koichi Miyake for technical assistance.
