The Research On The Best Time Of Bone Marrow Mesenchymal Stem Cell Transplant After Myocardial Infarction

Objective:To observe the effect of bone marrow mesenchymal stem cell transplant on the recovery of infracted myocardium in the different time points and to find an effective time window of bone marrow mesenchymal stem cell transplant.Methods:1.20 6-week-old male SD rats were used to obtain bone marrow mesenchymal stem cell.80 rats were randomly divided into control group (left anterior descending artery ligation inducing myocardial infarction), bone marrow mesenchymal stem cells (bone marrow mesenchymal stem cell, BM-MSC) transplant group. BM-MSC transplant group was divided equally into MI1h/MSC group, MI5h/MSC group, MI1W/MSC group and MI2W/MSC group according to the time(1h,5h,lw and 5w) of transplant after myocardial infarction. Bone marrow was obtained from the rat femur and BM-MSCs were cultured for 3 generations. BM-MSC was marked by DAPI in vitro. At corresponding time points, BM-MSCs were injected into surrounding and central of myocardial infarction with 50μL/points (2×106unit) suspension of bone marrow mesenchymal stem cell in each transplant subgroup. There was no intervention in the control group.2.Echocardiography and hemodynamics examination were used in comparing changes of heart function among the different groups in the 8 week after transplation. 3.Immunohistochemistry was used to observe the differentiation of BM-MSCs in myocardium.Results:1. Left ventricular end diastolic diameter (LVEDD) in MIlh/MSC group was (0.87±0.15) mm and LVEDD in the control group was (0.95±0.09) mm.There was no statistical difference between the two groups(P=0.27). LVEDD in MI5h/MSC group was (0.91±0.10) mm and LVEDD in the control group was (0.95±0.09) mm. There was no statistical difference between the two groups(P=0.62). LVEDD in MI1W/MSC group LVEDD was (0.85±0.06) mm and LVEDD in the control group was (0.95±0.09) mm. There was no statistical difference between the two groups(P=0.18). However, LVEDD in MI1W/MSC group was minimum.2. Left ventricular fractional shortening (FS) in the control group was (16.12± 14.21)%.FS in MIlh/MSC group was (28.31±6.74)%. FS in MI5h/MSC group was (28.35±11.44)%.FS in MI1W/MSC group was (16.69±14.95)%. There was no statistical difference among the three groups (P> 0.05). However. FS in MI1W/MSC group was the largest.3. Left ventricular end diastolic pressure(LVEDP) in the control group was (39.07±5.96). LVEDP in MIlh/MSC group was (23.37±12.50) mmHg. LVEDP in MI5h/MSC group was (21.79±8.64) mmHg. LVEDP in MI1W/MSC group was (14.61±2.67) mmHg. LVEDP in MI2W/MSC group was (17.31±3.16) mmHg. There was statistical difference between the control group and BM-MSC transplant group two groups(P<0.01). LVEDP in MIlh/MSC group and MI5h/MSC group was significantly higher than that in MI1W group (P=0.01 and P=0.04,respectively). There was no statistical difference in LVEDP between MI1W group and MI2W (P= 0.45). However, LVEDP in MI1W/MSC group was lowest.4. Motion of left ventricular posterior wall in the control group was decreased significantly compred with that in MIlh/MSC group, MI5h/MSC group, MI1W/MSC group and MI2 W/MSC group. However, range of motion of left ventricular posterior wall was more apparent in MI1W/MSC group.5. Cardiac specific proteins (cTnT) and cell gap junction protein connexin 43 were expressed in BM-MSC in BM-MSC transplant group.Conclusion:1. BM-MSC transplant can improve cardiac function after myocardial infarction.1 week after myocardial infarction may be the best time of BM-MSC transplant.2. BM-MSC can differentiate into cadiocyte.