| Object:To investigate the molecular mechanism of Total flavonoids of propolis(TFP) on pathological cardiac hypertrophy(PCH) and heart failure in mice based on PI3K/AKT signaling pathway. Methods:In present study, Eight-week-old male mice were anesthetized with 1.5% isoflurane. Alzet osmotic mini-pumps containing PBS or isoproterenol(ISO) were surgically implanted subcutaneously in the interscapular region of the mouse. ISO was calibrated to release the drug at a rate of 15 mg?kg-1?d-1 for 7 d. Different doses of TFP(1–50 mg?kg-1?d-1) were intragastrically administered for 7 d. The adult mice were continuously infused with ISO(25 mg?kg-1?d-1) for 7 d to experimentally induce heart hypertrophy. Then the m RNA expression of ANF and ?-MHC was detected to ensure the best dose of TFP on heart hypertrophy. Then the animals were randomly divided into four groups: control group, ISO group, TFP(25 mg?kg-1?d-1) group, TFP(25 mg?kg-1?d-1) + ISO group. Cardiac hypertrophy, apoptosis injury, inflammatory factors and other changes were detected by using QPCR, Western blot, spectrophotometry, HE and Masson staining techniques.Results: 1. Effect of TFP on the expression of ANF and ?-MHC in ISO-induced PCH miceTFP significantly inhibited ANF and ?-MHC m RNA levels increased in ISO-induced PCH mice, in a dose-dependent manner. TFP(50 mg?kg-1?d-1) exerted no additional benefit to reduce heart hypertrophy; thus, we selected 25 mg?kg-1?d-1 for the following experiments. 2. Effect of TFP on cardiac dysfunction in ISO-induced PCH miceCompared to the control group, LVIDs?LVIDd and LVVs in ISO group were significantly increased, while EF, FS were significantly decreased(P<0.05), there are significant differences; Compared to ISO group, LVIDs, LVIDd and LVVs in TFP 25 mg?kg-1?d-1 + ISO group were significantly decreased, and EF, FS were significantly increased(P<0.05). 3. Effect of TFP on the extent of myocardial hypertrophy in ISO-induced PCH miceCompared to the control group, HW and HW/BW, CM cross-sectional area, ANF m RNA and protein levels in ISO group were significantly increased(P<0.05), HE staining showed pathological injury; Compared to ISO group, HW and HW/BW, CM cross-sectional area, ANF m RNA and protein levels in TFP 25 mg?kg-1?d-1 +ISO group were significantly decreased(P<0.05), and pathological damage alleviated. 4. Effect of TFP on myocardial fibrosis in ISO-induced PCH miceCompared to the control group, ?-SKA in ISO group was significantly increased(P<0.05), whereas MMP-9 decreased, but no significant difference, Masson staining showed that the myocardial cell death, and accompanied by myocardial fibrosis; Compared to ISO group, ?-SKA in TFP 25 mg?kg-1?d-1 + ISO group was significantly decreased(P<0.05), whereas MMP-9 increased, but no significant differences, also against ISO-induced myocardial fibrosis. 5. Effect of TFP on apoptotic damage in ISO-induced PCH miceISO group showed significant cardiac tissue abnormalities, including cytoplasmic vacuolization, muscle fiber loss, mitochondrial swelling, chromatin condensation, and myocardial necrosis. Caspase-8,-9,-3 activity were increased, and the m RNA expression of p53, TNFR and Fas were increased(P<0.05); while TFP 25 mg?kg-1?d-1 might be able to fight against the above-mentioned abnormal in myocardial tissue, and could also make Caspase-8,-9,-3 activity decrease, and the m RNA expression of p53, TNFR and Fas were reduced(P<0.05). 6. Mechanism of TFP on myocardial protection in ISO-induced PCH miceThe protein expression of p-AKT and p-AKT/AKT in ISO-induced mice were decreased; while TFP 25 mg?kg-1?d-1 + ISO group could make the expression of p-AKT and p-AKT/AKT increase(P<0.05); In addition, to added PI3 Ks inhibitors WM could against the effect of TFP on myocardial hypertrophy. Conclusions:1. TFP treatment significantly attenuated adverse cardiac dysfunction, hypertrophy, and associated disorder, such as fibrosis;2. TFP treatment significantly attenuated apoptotic damage and cardiac remodeling, which were correlated with the PI3K/AKT signaling. |
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