| Heart failure is the clinical manifestation terminal stage of various heart disease, including myocardial ischemia and apoptosis during the occurrence and development of the event. These are closely related to myocardial metabolism. Trimetazidine(trimetazidine, TMZ) is a kind of drugs can improve myocardial metabolism, belongs to the antianginal cardiovascular drug. TMZ optimizes the myocardial energy metabolism, relieves myocardial ischemia and improves myocardial contraction force by inhibiting fatty acid oxidation beta. TMZ has been successfully used in the treatment of ischemic heart disease, but the potential in the treatment of chronic heart failure remains to be further explored. This experiment is to observe in the same conditions the expression of caspase-3 protein, Bax protein and Bcl- 2 protein, compared with trimetazidine, ramipril,alone and combined on cardiomyocytes apoptosis in rats with chronic heart failure.Objective:For the research object was built heart failure rat model by abdominal aortic constriction. Then, the morphology of myocardium was observed by HE staining, myocardial ultra-structure was examined by transmission electronic microscopy, apoptopic index(AI)was detected by TUNEL assay. The expression of caspase-3 protein, Bax protein and Bcl- 2 protein in the myocardium of rats with heart failure were evaluated by immunohistochemiscal staining and RT-PCR. To investigate the effect of trimetazidine and ramipril alone or combined application on cardiomyocytes apoptosis in rats with chronic heart failure.Methods:1 60 clean male Wistar rats were bought. Randomly chosen 10 rats as control group, the remaining subjects were implemented abdominal aortic constriction. The success criteria of chronic heart failure Model for left ventricular end-diastolic pressure(LVEDP) was greater than or equal to 15 mm Hg. In addition, for the control group rats wereonly isolated abdominal aorta ligation. Building successful model rats were randomly divided into model group, the ramipril group,trimetazidine group and combination group.2 To the end of the experimental rats observed points, LVEDP and ±dp/dtmax were accurately record by multi-lead electric physiological instrument. Thoracotomy was performed and eviscerated the left ventricle in rats。Then,the left ventricular mass were weighed to calculate the left ventricular mass index(LVMI)3 Choosing HE staining to observe myocardial histopathological change of every rat.4 Using transmission electron microscopy to observe the left ventricular myocardial ultrastructure change of every rat.5 The apoptotic index of rats were detected by TUNEL assay.6 By SP immunohistochemical staining to detect the expression of caspase-3protein, Bax protein and Bcl-2 protein in rats’ left ventricular myocardial tissue.7 The expression level of caspase-3, Bcl-2 and Bax m RNA in rats were evaluate by RT-PCR method.Results:1 Research subjects’ hemodynamics parameters: The ± dp/dtmax of control group, heart failure model group, ramipril group, trimetazidine group and combination group were(5407.16±147.39)mm Hg/s﹠(4407.69±195.18)mm Hg/s,( 4104.64±193.93) mm Hg/s ﹠( 2813.56 ± 141.37) mm Hg/s,( 4522.32 ± 124.09) mm Hg/s ﹠( 3704.18 ± 135.10) mm Hg/s,( 4566.87±148.37) mm Hg/s ﹠( 3659.25 ± 118.98) mm Hg/s,(4896.10±164.03)mm Hg/s﹠(4147.61±227.07)mm Hg/s.The LVEDP of control group, heart failure model group, ramipril group, trimetazidine group and combination group were(5.63±0.98)mm Hg,(19.62±1.91)mm Hg,(12.24±1.43)mm Hg,(12.03±1.23)mm Hg,(7.48±1.41)mm Hg. The ±dp/dtmax in heart failure model group and three groups treatment group rats were significantly higher than the control group. The LVEDP in Trimetazidine group,Ramipril group and Combination group were obviously lower than the control group(P<0.01). Compared with model group, medication groups’ ±dp/dtmax were increased significantly and the LVEDP decreased obviously(P<0.01).The most obvious change was in combination group(P<0.01), but trimetazidine and ramipril group had no statistical difference(P>0.05).2 The LVMI in each groups: control group, heart failure model group, ramipril group, trimetazidine group, combination groupwere(2.15 ±0.12)‰,(4.44 ± 0.23)‰,(3.03 ± 0.23)‰,(2.91 ± 0.23)‰,(2.51 ± 0.34)‰. Compared with control group, the LVMI of model group were increased significantly(P < 0.01).Compared with model group, the LVMI of drug feeding groups were decreased(P < 0.01), and two drugs combination group decreased mostly(P < 0.01).3 Each groups’ rats myocardial tissue pathology change: HE staining: the sham group rats myocardial cells packed closely, arranged neatly. morphology, and the structure was clear. Model group rats myocardial cell arranged loosely, disordered, became myocyte hypertrophy and edema, and the structural was fuzzy. Compared with the model group,the drug intervention group rats had obvious changes, the combination group improve the most significantly.4 The left ventricular myocardial tissue ultrastructure changes in each group rats: the sham group rats myocardial cell and myofiber arranged neatly. The structure of mitochondria and sarcomere were integrated. The mitochondria are uniform, and the mitochondrial cristae were complete. Part of myofilament in the model group rats fractured and arranged loosely. The mitochondria were not of uniform size and swelled irregularly. Their cristae fractured and become fuzzy. Compared with the model group, the drug intervention group rats had obvious changes, the combination group improve the most significantly.5 The AI in all groups: TUNEL method was used to detect myocardial apoptosis. The AI in control group, heart failure model group, ramipril group, trimetazidine group and combination group were(1.68±0.76)%,(40.03±1.53)%,(23.84±1.74)%,(23.77±1.57)%,(15.64±1.67)%. Compared with control group, the AI in heart failure model group were increased significantly(P<0.01). Compared with CHF model group, the AI in three treatment groups were decreased significantly(P<0.01). It was the combination group which changed most significantly(P<0.01).6 The expression of caspase-3 protein, Bax protein and Bcl- 2 protein in left ventricular myocardium of each experimental rats was estimated by SP immunohistochemical staining.The expression trend of caspase-3 protein was similar to Bax protein’s.The control group had no obvious tan granule in cell, but heart failure model group rats cells have obvious tan particle deposition. Drug intervention groups’ positive reaction were the weaker. The weakest was the combination group. The expression of Bcl- 2 protein in control group had the strongest positive reflection, but in heart failure model group had no obvious positive reaction. Drug intervention groups were significantly increased. The combination was stronger than drug alone intervention groups and lower than control group.7 To detect the m RNA level of caspase-3, Bax and Bcl- 2 in left ventricular myocardial tissue of each group rats by RT-PCR: Compared the sham group, the m RNA level of caspase-3, Bax in model groups increased obviously(P<0.01),but the m RNA level of Bcl-2 reduced(P<0.01).Compared with the model group, the m RNA level of caspase-3, Bax in Drug intervention groups were significantly reduced.(P<0.01),but the m RNA level of Bcl-2 were significantly increased. Above indexes in the ramipril group and trimetazidine group had no significant difference(P>0.05). Especially,the m RNA level of caspase-3, Bax in the combination group were lower than in drug alone intervention groups,but the m RNA level of Bcl-2 were higher than in drug alone intervention groups(P<0.01).Results:1 Trimetazidine can effectively suppress myocardial cell apoptosis in chronic heart failure rats.2 In the inhibition of myocardial apoptosis in chronic heart failurerats, trimetazidine and ramipril have similar clinical curative effect.Two kinds of medicine have synergy, so the combination curative effect is better. |
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