KMUP-3 Attenuates Angiotensin II Induced Abdominal Aortic Aneurysm Formation in Apolipoprotein E-Knockout Mice

• Main Authors: Ching-Wen Chang, 張瀞文
• Other Authors: Jwu-Lai Yeh
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/31666994379304437601

碩士 === 高雄醫學大學 === 醫學系藥理學科碩士班 === 104 === Vascular smooth muscle cells (VSMCs) apoptosis, occurring in many arterial diseases, including atherosclerosis, aneurysm formation and cell calcification, accelerates inflammation, smooth muscle cells loss and vascular remodeling. Abdominal aortic aneurysm (AAA), a chronic degenerative process of the abdominal aorta, is a life-threatening disease in the elderly population, especially in men. Pathologically, AAAs are associated with inflammation, smooth muscle cell apoptosis and matrix degradation. In our previous studies of high glucose-induced cardiomyocytes injury and diabetes rats’ model, we found that KMUP-3 can induce autophagy in cardiomyocytes. And reduce cardiac injury and improve cardiac functions. Vascular calcification is a sign of a degenerative inflammatory process involved in the arterial wall and it is a main risk factor in the cardiovascular field and may strengthen the rupture risk assessment of the AAA. We further investigated whether KMUP-3 can promote autophagy activity and attenuate VSMCs calcification, AAA formation and improve cardiac functions in apoE−/− mice. In this study, we used β-glycerophosphate (β-GP) to mimic the hyperphosphatemia condition which had already been proved to induce apoptosis in VSMCs. Primary 7-8 weeks male SD rats’ VSMCs were incubated in 10 mM β-GP in the presence or absence of KMUP-3 (0.1-10 μM) for 48 hr and 10 days. An experimental AAA model was induced via osmotic mini-pump (Alzet 2004) which was implanted into 24 weeks male apoE−/− C57BL/6 mice in order to administrate saline or angiotensin II (Ang II) s.c. at a dose of 1,000 ng/kg/min for 28 days, during which mice were fed with a Western diet (0.15% cholesterol and 21% milk fat). KMUP-3 was intraperitoneally injected at a dose of 1 mg/kg/day. At the end of the experimental period, we used transthoracic echocardiography to measure cardiac function, such as left ventricular end-systolic dimension (LVESD), LV end-diastolic dimension (LVEDD) and LV fractional shortening (%FS). We found that KMUP-3 treatment attenuated β-GP-induced cell death and VSMCs calcification by MTT assay, Alizarin Red S staining, Von Kossa staining, calcium deposition and ALP activity. Additionally, KMUP-3 also inhibited β-GP-induced apoptosis, with associated increased the activity of Bcl-2, and decreased the expression of Bax. The Annexin V/PI positive cell numbers in flow cytometry are also decreased. KMUP-3 significantly enhanced autophagy markers in VSMCs, such as LC3-II, ATG5 and phosphorylation of AMPK in pretreatment manner. In our animal model, KMUP-3 could not only reduce the formation of the aneurysm and decrease α-SMA depletion, vascular fibrosis, elastin degradation and calcium deposition at abdominal aorta, but also improve cardiac function of Ang II-infused APOE mice. The results in our studies indicated that KMUP-3 could dose-dependently attenuate β-GP-induced calcium deposition, ALP activity, the expression of angiogenesis, apoptosis and osteochondrogenic-related proteins through autophagy. Furthermore, KMUP-3 also has great capabilities to restrict AAA dilation. Based on our results, KMUP-3 may be a potent agent to decrease VSMCs calcification and AAA formation.