Protective Effect of Trimetazidine on Potassium Ion Homeostasis in Myocardial Tissue in Mice with Heart Failure

Figures

• 

  Figure 1. Change in cardiac function in the NC, MOD, and TMZ groups. After modeling, decreased cardiac function was found in the MOD group. However, after TMZ treatment, cardiac function was restored (a, b). (c) A graph representing ejection fraction. ∗∗∗P < 0.001 vs. NC group; ##P < 0.01 vs. MOD group.

• 

  Figure 2. Histopathological characterization of the myocardial tissues of C57BL/6 mice in each group. After different treatments, the mice in each group were sacrificed, and the myocardial tissues were isolated and sectioned. After staining with hematoxylin and eosin (H&E) solution, the sections were observed under a microscope. Magnification: 200x. (a) Normal control group, (b) model group, and (c) TMZ group (10 mg/kg/d).

• 

  Figure 3. Mitochondrial ultrastructure of cardiomyocytes: (a) NC group; (b) MOD group; (c) TMZ group.

• 

  Figure 4. Determination of ATP contents in myocardial tissues in the NC, MOD, and TMZ groups. The results showed that the ATP content of MOD mice was lower than that of the NC group. However, after TMZ treatment, the ATP content in the myocardial tissues was higher than that in the MOD group. Compared to the NC group, ∗∗∗P < 0.001; compared to the MOD group, ##P < 0.01. n = 6.

• 

  Figure 5. Determination of the expression of ATP1α1 at the mRNA and protein levels in myocardial tissues in C57BL/6 mice after different treatments. After relevant treatments, ATP1α1 mRNA and protein levels were measured by Q-PCR and ELISA, respectively. The results show that the expression of ATP1α1 in the myocardium in the MOD group was significantly lower than that in the NC group. After TMZ treatment, the Na+-K+ ATPase protein level was significantly elevated compared to that in the MOD group. Compared to the NC group, ∗∗P < 0.01 and ∗∗∗P < 0.001; compared to the MOD group, #P < 0.05 and ###P < 0.001. n = 5 for the determination of ATP1α1 mRNA levels, n = 6 for the determination of Na+-K+ ATPase protein levels.

• 

  Figure 6. Determination of Na+-K+ ATPase activities in the myocardial tissues of C57BL/6 mice after different treatments. An HF mouse model was induced by doxorubicin administration, and the mice received different treatments for 6 weeks. At the indicated time, the mice were sacrificed after anesthesia, and myocardial tissues were isolated, ground under liquid nitrogen, and centrifuged at 2500 rpm for 10 min. Then, the supernatants were collected to measure Na+-K+ ATPase activity. Compared to the NC group, ∗∗∗P < 0.001; compared to the MOD group, #P < 0.05. n = 6.

• 

  Figure 7. Measurement of K+ flux across the myocardial tissue in C57BL/6 mice in the NC, MOD, and TMZ groups. After relevant treatments, C57BL/6 mice were first anesthetized, the myocardial tissue was exposed, and then NMT was used to measure the real-time K+ flux across the myocardial tissue (a). Histogram analysis shows the trend of K+ flux measured by the NMT technique in C57BL/6 mice in the TMZ group (b). ∗∗∗P < 0.001 vs. NC group.