Astragaloside IV inhibits MAPK pathway and promotes mitochondrial autophagy in rats with heart failure

Fig. 1. Astragaloside IV (AS-IV) alleviates myocardial fibrosis in heart failure rats. Representative images of myocardial sections stained with Masson’s trichrome in each group: Control, abdominal aortic constriction (AAC), AAC + AS-IV (20 mg/kg), and AAC + AS-IV (80 mg/kg). Collagen fibers are stained blue, while cardiomyocytes are stained red. The fibrosis relative area was quantified by ImageJ. Scale bar = 100 μm. ***p < 0.001, ###p < 0.001.

Fig. 2. Astragaloside IV (AS-IV) attenuates cardiac hypertrophy in heart failure rats. Representative immunofluorescence images of cardiac tissue stained with WGA (green) to outline cell membranes and DAPI (blue) to label nuclei in the control, abdominal aortic constriction (AAC), and AS-IV-treated groups. Merged images are shown in the third row. The lower panel shows quantitative analysis of cardiomyocyte area expressed as a percentage of the control group. Data are presented as mean ± SD (n = 6 per group). ***p < 0.001 vs. Control; ###p < 0.001 vs. AAC. Scale bar = 100 μm.

Fig. 3. Astragaloside IV (AS-IV) improves mitochondrial function in heart failure rats. (A) ATP content and MnSOD activity in myocardial tissues were measured in four groups: Control, abdominal aortic constriction (AAC), AAC + AS-IV (20 mg/kg), and AAC + AS-IV (80 mg/kg). (B) Representative fluorescence images of myocardial sections stained with DHE (red) for ROS detection and DAPI (blue) for nuclei in each group: Control, AAC, AAC + AS-IV (20 mg/kg), and AAC + AS-IV (80 mg/kg). (C) Western blot and densitometric analysis of PGC-1α expression in the four experimental groups. (D) Western blot and quantification of TFAM protein levels in myocardial tissues from each group. (E) The activities of Complex I, II, and IV was detected by the kits in the indicated groups. Data are expressed as mean ± SD (n = 6 per group). ***p < 0.001 vs. Control; ##p < 0.01, ###p < 0.001 vs. AAC. Scale bar = 100 μm. MnSOD, manganese superoxide dismutase; DHE, dihydroethidium; ROS, reactive oxygen species.

Fig. 4. Astragaloside IV (AS-IV) activates mitochondrial autophagy in heart failure rats. (A) Western blot analysis and quantification of Parkin, p62, and Beclin1 expression in cardiac tissues from four groups: Control, abdominal aortic constriction (AAC), AAC + AS-IV (20 mg/kg), and AAC + AS-IV (80 mg/kg). β-actin was used as a loading control. (B) Western blot analysis of LC3-I and LC3-II and the corresponding LC3-II/LC3-I ratio in the same groups. Data are presented as mean ± SD (n = 6 per group). ***p < 0.001 vs. Control; ###p < 0.001 vs. AAC.

Fig. 5. Astragaloside IV (AS-IV) inhibits activation of the MAPK pathway in heart failure rats. Western blot analysis of phosphorylated p38 (p-p38), total p38, and β-actin in myocardial tissues from four groups: Control, abdominal aortic constriction (AAC), AAC + AS-IV (20 mg/kg), and AAC + AS-IV (80 mg/kg). The right panel shows the quantification of p-p38/p38 protein ratio. Data are presented as mean ± SD (n = 6 per group). ***p < 0.001 vs. Control; ###p < 0.001 vs. AAC.

Fig. 6. Astragaloside IV (AS-IV) suppresses autophagy and mitochondrial function via targeting MAPK pathway in H9c2 cells. (A) Western blot analysis of Parkin, p62, and β-actin in H9c2 cells from the indicated groups. (B) Western blot analysis of LC3II, LC3I, and β-actin in myocardial tissues from the indicated groups. The ratio of LC3II/LC3I was quantified. (C) Representative fluorescence images of myocardial sections stained with JCI monomer (red) and aggregates (green) and DAPI (blue) for nuclei in each group. Data are presented as mean ± SD (n = 6 per group). ***p < 0.001 vs. Control; ##p < 0.01, ###p < 0.001 vs. Dox. Scale bar = 100 μm. Dox, doxorubicin hydrochloride.