OBJECTIVETo investigate effect of Compound Danshen Dripping Pill (CDDP) on the inflammatory response of the myocardium of acute myocardial infarction (AMI) rabbits, to observe the therapeutic effect of CDDP combined intravenous transplantation of human umbilical cord blood mononuclear cells (HUCBMCs) on inflammatory response, pro-inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) , and heart function in the myocardium of AMI rabbits, and to explore the possible protective mechanisms of the combined therapy.

METHODSThe AMI model was successfully established by ligation of the left anterior coronary artery (LAD) in 40 healthy rabbits.Then they were randomly divided into four groups, i.e., the control group, the CDDP group, the transplantation group, and the combined group, 10 in each group. Rabbits in the control group received intravenous injection of 0.5 mL normal saline via ear vein within 24 h after AMI and then intragastric infusion of normal saline at 5 mL per day. Rabbits in the CDDP group received intravenous injection of 0.5 mL normal saline via ear vein within 24 h after AMI and then intragastric infusion of solution obtained by solving 270 mg CDDP in 5 mL normal saline per day. Rabbits in the transplantation group received intravenous injection of 0.5 mL normal saline labeled with green fluorescent protein (GFP) containing 3 x 10(7) of HUCBMCs via ear vein within 24 h after AMI and then intragastric infusion of normal saline at 5 mL per day. Rabbits in the combined group received intravenous injection of 0.5 mL normal saline labeled with GFP containing 3 x 10(7) of HUCBMCs via ear vein within 24 h after AMI and then intragastric infusion of solution obtained by solving 270 mg CDDP in 5 mL normal saline per day. At week 1 and 4 after treatment, cardiac function indices such as left ventricular fractional shorting (LVFS) and left ventricular ejection fraction (LVEF) were performed by echocardiography; the number of transplanted cells in the myocardium was found by GFP positive cells counted with fluorescence microscopy.The white blood cells in the myocardium stained with HE were determined by light microscope. The expressions of TNF-alpha protein in the myocardium were detected by immunohistochemical assay.

RESULTS(1) Compared with the control group at week 1 and 4 after treatment, the LVEF and LVFS were significantly improved in the CDDP, transplantation, and combined groups (P < 0.05). The cardiac function was significantly improved in the combined group than in the CDDP group and the transplantation group (P < 0.05). But there was no statistical difference in the latter two groups. (2) Compared with the control group, the number of white blood cells and the expression of TNF-alpha protein decreased significantly in the CDDP, transplantation, and combined groups at week 1 and 4 respectively after treatment. The number of white blood cells and expressions of TNF-alpha protein were significantly lower in the combined group than in the CDDP group and the transplantation group (P <0.05). But there was no statistical difference in the latter two groups. (3) GFP-positive cells were found to be distributed in the peri-myocardial infarction area in the transplantation group and the combined group at week 1 and 4 after transplantation. Besides, the number of the GFP positive cells was much more in the combined group than in the transplantation group (P < 0.05).

CONCLUSIONSThe findings indicated that the combination of CDDP with intravenous transplantation of HUCBMCs in the treatment of AMI rabbits could elevate the survival rate of transplanted cells, and further improve the heart function. The possible mechanisms might be related to attenuating local inflammation of myocardium, and inhibiting enhanced expressions of pro-inflammatory cytokine TNF-alpha protein.