| Objective To study the effects of human umbilical cord mesenchymal stem cells(h UCMSCs) intramuscular injection on myocardium and angiogenesis in rats with dilated cardiomyopathy.Methods 100 rats were randomly divided into control group(n=15) and dilated cardiomyopathy group(to abbreviate: DCM group, n=85). Rats in DCM group were treated with Adriamycin by intraperitoneal injection of 2.0mg/kg dose per week for 8 weeks, in order to induce DCM. At 2 weeks after successful establishment of DCM,60 surviving rats were randomized into 3 groups and treated with h UC-MSCs or DMEM by intramuscular injection. Rats in the Model Group(to abbreviate: DMEM group, n=20) received intramuscular infusion 2ml DMEM alone. Rats in Low dose Group(n=20) underwent intramuscular infusion of 1×106 h UC-MSCs/2ml in DMEM. Rats in High dose Group(n=20) underwent intramuscular infusion of 10×106 h UC-MSCs/2ml in DMEM. At 4 weeks after administration of h UC-MSCs, Echocardiography was performed to evaluate the cardiac function, plasma brain natriuretic peptide(BNP) level was detected by Enzyme Immunoassay kit(EIA). Myocardial microvessel density(MVD) was detected by using anti-CD34 monoclonal antibody and transmission electron microscopy(TEM) were performed to observe the ultrastructure of MVD. Myocardial genes(Slit-2, Robo-1, and Robo-4) were detected by real-time PCR and the protein(HGF,VEGF and LIF) expressions were detected by Western blot analysis.Results At 4 weeks after administration of h UC-MSCs, left ventricular ejection fraction(LVEF) and left ventricular fractional shortening(LVFS) were significantly increased in low-dose [ LVEF(66.10±1.93)% to(72.27±2.44)%, P < 0.01, LVFS(31.00±1.71) to(34.96±2.08)%,P<0.05 ] and high-dose [ LVEF(66.31±2.97)% to(70.92±2.68)%, P < 0.01, LVFS(31.57±2.45)% to(33.49±2.19)%, P < 0.05] h UCMSCs group compared to those before the injection. Differences did not reach statistical significance in the LVEF and LVFS in DMEM group rats compared to those before the injection. The plasma level of BNP was significantly declined in the h UC-MSCs treated DCM rats as compared to those before the treat Low dose group [(352.68±41.25) pg/ml to(202.68±20.38) pg/ml, P < 0.01], High dose group [(355.79±48.32) pg/ml to(193.62±15.41) pg/ml,P<0.01] and in DMEM treated rats showed increased compared to those before the treat [( 365.42±61.81) pg/ml to(431.26±52.80) pg/ml,P<0.05]. Quantitative analysis demonstrated that MVD was significantly higher in Low-dose and High-dose h UC-MSCs treated DCM rats than in the DMEM treated DCM rats[(84.00±19.18) /mm2 and(86.67±20.88) /mm2 vs(27.14±13.97) /mm2, P<0.01] and it’s no significant difference between DMEM group and Control group [(27.14±13.97) / mm2 vs(16.43±5.71) / mm2, P>0.05]. Slit-1 and Robo-1 m RNA expression in Low-dose and High-dose group were substantially higher than those detected in the DMEM group. Robo-4 m RNA expression did not differ among all group. Western blot analysis showed that myocardial contents of HGF,VEGF, and LIF in the Low-dose and High-dose h UCMSCs DCM group were significantly increased compared with DMEM group.Conclusions h UC-MSCs transplantation by intramuscular injection improved cardiac function in rat model of DCM, and it was raise Slit-2, Robo-1, HGF, LIF and VEFG expression in myocardium to induced angiogenesis. The beneficial effects of h UCMSCs might be mediated by their ability to supply large amounts cytokines through paracrine mechanism. |
