Explore Protective Mechanism of Ginseng Radix et Rhizoma, Notoginseng Radix et Rhizoma and Chuanxiong Rhizoma Extract on Cardiac Aging in Diabetic Mice Through AMPK/mTOR Pathway / 中国实验方剂学杂志

ABSTRACT

Objective:To explore the protective mechanism of Ginseng Radix et Rhizoma, Notoginseng Radix et Rhizoma and Chuanxiong Rhizoma (GNC) extracts on cardiac aging in diabetic mice by observing the activation of AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, changes of cardiac pathomorphological and related senescent proteins. Method:C57BL/6 male mice, SPF level, were randomly divided into normal control group and high-glucose group. The mice in high-glucose group were intraperitoneally injected with streptozotocin (STZ) and fed with high-fat diet. After successful modeling, they were randomly divided into model group, low-dose GNC group (0.819 g·kg-1), high-dose GNC group (1.638 g·kg-1) and metformin group (150 mg·kg-1). The drug was administered by gavage once a day for a continuous period of 9 weeks. 4-week-old male C57BL/6 mice were normally fed for 1 week as a youth group. General conditions of mice were observed. Hematoxylin-eosin (HE) staining combined with transmission electron microscope (TEM) was used to observe the cardiac pathomorphology in mice. Von Kossa staining was used to determine the degree of calcium salt deposition in cardiac micro vessels. Western blot was used to detect the activation of signaling pathways in myocardial tissue of mice, as well as the expression levels of matrix metalloproteinases-2 (MMP-2), tumor suppressor p53 (p53), and phospho-tumor suppressor p53 (p-p53). Result:As compared with the normal group, the blood glucose in the model group increased (P<0.01), as compared with the model group, the blood glucose in each administration group decreased significantly (P<0.05, P<0.01). The results of three pathological morphology experiments (HE, TEM, and Von Kossa) showed that as compared with the normal control group, the mice in model group showed cardiomyocytes hypertrophy, disordered arrangement of myocardial fibers, focal dissolving and necrosis, mitochondria swelling, degeneration, crest fracture, vacuolar alteration, disordered microvascular structure of the heart, uneven staining, and a large amount of calcium deposition in tunica media and intima. As compared with the model group, the pathomorphological changes of mice in each administration group were improved in varying degrees. Compared with the normal group, the expression levels of MMP-2, p53 and p-p53 protein in the model group were significantly increased (P<0.05, P<0.01), the protein ratios of p-liver kinase B2(LKB1)/LKB1, p-AMPK/AMPK were significantly decreased (P<0.05, P<0.01), and the average gray level of p-mTOR/mTOR and p-p70S6 kinase(p70S6k)/p70S6k protein was significantly increased (P<0.05, P<0.01), while the protein ratios of p-mTOR/mTOR, p-p70S6k/p70S6k were increased (P<0.01). As compared with the model group, the expression levels of MMP-2, p53 and p-p53 protein in each administration group were significantly decreased (P<0.05, P<0.01), the protein ratios of p-LKB1/ LKB1, p-AMPK/AMPK were significantly increased (P<0.05, P<0.01), while the protein ratios of p-mTOR/mTOR and p-p70S6k/p70S6k were decreased (P<0.05, P<0.01). Conclusion:STZ combined with high-fat diet can induce cardiac aging in mice, and GNC can improve cardiac aging in diabetic mice, which may be related to the inhibition of AMPK/mTOR pathway related protein expression.