| Objective 1.To observe the migration and differentiation of rat bone marrow mesenchymal stem cells(BMSCs) in infracted heart tissue. 2.To observe the therapeutic effect of the transplatation of BMSCs, neonatal rat's cardiomyocytes (NRCs) and BMSCs combined with NRCs on the myocardial infartion in rats.Methods 1.Isolation,purification,expansion and label of BMSCs:The BMSCs cells were collected from bone marrow of SD rat's(150±5g) femord bones,cultured , passaged in vitro,and purified by density grads centrifugal and adhesive-screening methods.The fourth generation BMSCs were labelled with CM-Dil. 2.Isolation purification of NRCs:The NRCs were collected from the heart of neonatal rats (born one day),they were digested with steapsin and different speed of adhesive-screeing . 3.The process of producting transplanted cells:The 2×106 cells were admixtured with PBS. 4.Experimental animals and groups:The 44 SD rats weight about 300±20g were randomly divided into 4 groups.①Control group (C group,n=10):The rats were received the PBS(0.15ml) in infarction area and two borders②BMSCs group (M group,n=12):The rats were received the BMSCs (2×106 /0.15ml) in infarction area and two borders.③NRCs group (N group,n=10):The rats were received the NRCs (2×106 /0.15ml) in infarction area and two borders.④BMSCs+ NRCs group (MN group,n=12):The rats were received the BMSCs (2×106 /0.15ml) in infarction area and two borders. 5.The cells transplantation:Experiment myocardial infarction was producted in rats by ligating the left antenrior descending coronary artery,the transplanted cells were directly injected into the infracted area and borders. 6. 4 weeks after operation, the heart function was assessed by echocardiography and the hemodymamic left ventricular measurements.The hearts were removed,to investigate the BMSCs survival, distribution, transfer, differentiation and the density capillary in infarction area by fluorescence microscope.Results 1. The morph of collectted BMSCs were identical,the BMSCs were proliferated well ,cultured by density grads centrigal and adhesive-screening methods. The isolation, cultured NRCs growed well, beated on rhythm. 2.The myocardial infartion was successfully producted by ligating antenrior descending coronary after tracheotormy.When the hearts of rats were injured ,there were Q waves and elevate ST segments in electrocardiogram. Hematoxylin and eosin showed that the cells necrosis,infiltrated and with fabric hyperplasy. 3. After celluar cardiomyoplasty, the heart function of rats assessed with echocardiography and the hemodymatic left ventricular measurements.The heart function was significantly improved in MN group or M group than that in C group,and MN group than that in M group.[Ejection fraction(%)(MN group 47.81±3.61vs M group 44.41±2.45 vs C group 40.52±2.61,P<0.05;N group 43.64±3.81vs the others,P>0.05) .Maximum left ventricular pressure rising rate +dp/dt(mmHg/s)(MN group 3444.23±327.45 vs M group 3167.26±266.98 vs C group 2879.78±239.00, P<0.05;N group 2976.85±108.85 vs the others , P>0.05 ) .Dropping rising -dp/dt(mmHg/s)(MN group 3156.60±297.73 vs M group 2892.38±226.18 vs C group 2060.60±281.40 , P <0.05; N group 2770.35±110.23 vs the others,P>0.05)]. 4.The density of capillary was assessed by fluorescence miscroscope. The density of capillary was higher in MN group or in M group than that of C group and MN group than that of M group. [The density of capillary(N/HPF) (MN group 5.73±1.47 vs M group 3.93±0.91 vs C group 2.04±0.87,P <0.05; N group 3.10±1.11vs the others,P>0.05)]. 5.The distributing and differentiation of BMSCs.The positive CM-Dil cells were observed at infracted area in M groups and MN groups .The cells positive for both CM-Dil and cTnT were also observed in M groups and MN groups, it indicated that the transplanted BMSCs were able to survive and differentiate into cardiac-like cells .Conclusions 1.BMSCs ,able to survive and differentiate into cardiac-like cells in infraction heart, can promote angiogenesis and then improve heart function. 2.BMSCs cotransplantation with NRCs can obviously improve heart function ,which may result from a better mircoenviroment and a stronger angiogenesis.
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