Objective: To explore the effects of compound Danshen dripping pills (CDDP) and CDDP combined with transplantation of human umbilical cord blood cells (HUMNCs) on the inflammatory response, oxidative stress, myocardial cell apoptosis and cardiac function, and also to investigate the possible mechanisms of the combined therapy in the acute myocardial infarction (AMI).
Methods: Rabbit model of AMI successfully established by ligation of the left anterior coronary artery (LAD). Forty rabbits were randomly divided into 4 groups (n=10 per group): a control group, injected with 0.5 mL of saline in 24 h after AMI and then gavaged with 5 mL of saline daily; a CDDP group, injected with saline 0.5 mL after AMI and then gavaged with CDDP (270 mg/d) daily; a transplantation group, injected with 0.5 mL of saline contained 3 × 10(7) HUCBMCs [labeled with green fluorescent protein (GFP)] and then gavaged with 5 mL of saline daily; a combined group, injected with 0.5 mL of saline contained 3 × 10(7) HUCBMCs (labeled with GFP) and then gavaged with CDDP (270 mg/d) daily. Cardiac function index such as left ventricular fractional shorting (LVFS) and ejection fraction(LVEF) were measured by echocardiography; the pathological changes were observed by HE staining and the white blood cells in the myocardium were determined by light microscopy. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in myocardium were detected by nitrotetrazolium blue chloride (NBT) and thiobarbituric acid colorimetric measurement respectively. The number of transplanted cells in the myocardium was examined by GFP positive cells counted with fluorescence microscopy.
Results: 1) Compared with the control group (at 1 or 4 week), LVEF and LVFS were significant improved in the CDDP group, the transplantation group and the combined groups (all P<0.05), the improvement degree of cardiac function in the combined group was the most significance. There was no significant difference between the CDDP group and the transplantation group. 2) Compared with the control group (at 1 or 4 week), the number of white blood cell, myocardial cell apoptosis ratio were decreased significantly in the CDDP group, the transplantation group and the combined groups (all P<0.05), this decrease in the combined group was the most significance, and there was no significant difference between the CDDP group and the transplantation group. 3) Compared with control (at 4 week), the SOD activity was increased significantly, and MDA content in myocardium was decreased in the CDDP group, this change in the combined group was the most significance. 4) GFP-positive cells were found to be present in the peri-myocardial infarction area in the transplantation group and the combined group at 1, 4 weeks post-transplantation. The number of the GFP positive cells in the combined group was more than that in the transplantation group (P<0.05).
Conclusion: The intravenous transplantation of HUMNCs combined with the CDDP in the treatment of rabbits with AMI could increase the survival rate of transplanted cells and inhibit the myocardial cell apoptosis, therefore improve the heart function. The possible mechanism of the combined treatment may be involved in the inhibition of the inflammatory response and oxidative stress in the myocardium following AMI.