臺灣博碩士論文加值系統

先前實驗室研究結果顯示高脂飼料誘導大鼠肥胖模式中，肥胖造成的胰島素阻抗發展過程中，脂肪組織中環氧化合酶-2的活化扮演著重要的角色。因此本篇文章利用高脂肪飼料餵食誘導肥胖及瘦素接受器缺乏肥胖小鼠，更進一步探討給予選擇性第二型環氧化合酶抑制劑對於脂肪組織發炎和胰島素阻抗的直接與間接的影響。C57BL/6小鼠分別餵食正常飼料 (CONT) 或高脂肪飼料 (HFa)，合併給予安慰劑或選擇性第二型環氧化合酶抑制劑Celecoxib持續16週。HFa給藥組又可再分為給予抑制劑後體重較高組 (HFa-CelHBW) 和體重較低組 (HFa-CelLBW)。另外利用db/m、db/db老鼠給予安慰劑或選擇性第二型環氧化合酶抑制劑Celecoxib為期八週。餵食高脂肪飼料組及db/db老鼠體重顯著上升，併給予選擇性第二型環氧化合酶抑制劑後，部分高脂肪飼料餵食小鼠體重下降，另一部分則無改變；瘦素接受器缺乏肥胖小鼠體重則不受影響。給予選擇性第二型環氧化合酶抑制劑後，無論是在高脂肪飼料餵食誘導肥胖或db/db小鼠，皆會使因肥胖而造成血糖及胰島素升高的趨勢下降。C57BL/6小鼠餵食高脂飼料後，脂肪組織中COX-2、MCP-1 、TNF-α 及血漿中瘦素表現量顯著性上升。而在合併給予選擇性第二型環氧化合酶抑制劑後抑制這樣上升的趨勢，又特別以HFa-CelLBW組特別明顯。HFa及db/db老鼠脂肪細胞有顯著性肥大的現象，而給予選擇性第二型環氧化合酶抑制劑後會使肥大的脂肪細胞變小，且在HFa_Cel組較為明顯。實驗結果顯示選擇性第二型環氧化合酶抑制劑-Celecoxib可透過直接及間接改善中樞瘦素的敏感性而使體重下降，進而改善因肥胖所誘導脂肪組織發炎的情形。

Our previous studies suggested that COX-2 activation in obese adipose tissue plays a crucial role in the development of insulin resistance and fatty liver in high-fat-fed rats. The aim of this study was to further clarify the direct and indirect body-weight-reducing effects of COX-2 inhibition on obesity-induced adipose inflammation in high fat-fed and db/db mice. The mice were fed regular diet (CONT) or high-fat diet ad libitum (HFa), co-treated with vehicle or selective COX2 inhibitor-celecoxib (CONT-Cel) or (HFa-Cel) for 16 weeks. HFa-Cel group was further divided into high-body-weight (Hfa-CelHBW) and low-body–weight (Hfa-CelLBW) subgroups. In the other set of experiment, db/db obese mice were treated with or without celecoxib for 8 weeks. The body weight was significantly increased in mice with high fat feeding and db/db mice at the end of the study. Celecoxib treatment reduced body weight gain only in part of high-fat fed mice , but not in db/db mice. COX-2 inhibition significantly suppressed obesity-induced increases in blood glucose and plasma insulin in HFa and db/db mice. The augmentation of COX-2, MCP-1 and TNF-α gene expressions in obese adipose tissues and plasma leptin levels were significantly suppressed in HF-fed mice combined with celecoxib treatment, especially in HFa-CelLBW. In conclusion, it is suggested that selective COX-2 inhibition could significantly suppress obesity-induced adipose inflammation mediated by direct and indirect body-weight-reducing effects which might be mediated by improving the central leptin sensitivity

圖目錄 II
中文摘要 IV
Abstract VI
第一章、前言 1
第一節、肥胖的定義及盛行率 1
第二節、肥胖所造成的脂肪組織慢性發炎與第二型糖尿病 2
第三節、肥胖所造成的脂肪組織慢性發炎 4
第四節、Cycloxygenase-2 (COX-2)的活性與肥胖導致脂肪組織發炎 5
第五節、瘦素(leptin) 8
第六節、第二型環氧化合酶與瘦素 10
第七節、假說 11
第二章、實驗目的 12
第三章、材料與方法 13
第一節、實驗材料 13
第二節、實驗設計 19
第三節、實驗方法 22
第四章、實驗結果 32
 高脂肪飼料誘導肥胖模式 32
 瘦素接受器缺乏小鼠肥胖模式 37
討論 42
附 圖 49
參考文獻 69

1.Xu, H., et al., Chronic inflammation in fat plays a crucial role in the development of obesity-related insulin resistance. J Clin Invest, 2003. 112(12): p. 1821-30.
2.Hotamisligil, G.S., N.S. Shargill, and B.M. Spiegelman, Adipose expression of tumor necrosis factor-alpha: direct role in obesity-linked insulin resistance. Science, 1993. 259(5091): p. 87-91.
3.Hotamisligil, G.S. and B.M. Spiegelman, Tumor necrosis factor alpha: a key component of the obesity-diabetes link. Diabetes, 1994. 43(11): p. 1271-8.
4.Uysal, K.T., S.M. Wiesbrock, and G.S. Hotamisligil, Functional analysis of tumor necrosis factor (TNF) receptors in TNF-alpha-mediated insulin resistance in genetic obesity. Endocrinology, 1998. 139(12): p. 4832-8.
5.Uysal, K.T., et al., Protection from obesity-induced insulin resistance in mice lacking TNF-alpha function. Nature, 1997. 389(6651): p. 610-4.
6.Ventre, J., et al., Targeted disruption of the tumor necrosis factor-alpha gene: metabolic consequences in obese and nonobese mice. Diabetes, 1997. 46(9): p. 1526-31.
7.Moller, D.E., Potential role of TNF-alpha in the pathogenesis of insulin resistance and type 2 diabetes. Trends Endocrinol Metab, 2000. 11(6): p. 212-7.
8.Xu, H., et al., Altered tumor necrosis factor-alpha (TNF-alpha) processing in adipocytes and increased expression of transmembrane TNF-alpha in obesity. Diabetes, 2002. 51(6): p. 1876-83.
9.Sartipy, P. and D.J. Loskutoff, Monocyte chemoattractant protein 1 in obesity and insulin resistance. Proc Natl Acad Sci U S A, 2003. 100(12): p. 7265-70.
10.Goossens, G.H., The role of adipose tissue dysfunction in the pathogenesis of obesity-related insulin resistance. Physiol Behav, 2008. 94(2): p. 206-18.
11.Guilherme, A., et al., Adipocyte dysfunctions linking obesity to insulin resistance and type 2 diabetes. Nat Rev Mol Cell Biol, 2008. 9(5): p. 367-77.
12.Krysiak, R., B. Okopien, and Z.S. Herman, [Adipose tissue: a new endocrine organ]. Przegl Lek, 2005. 62(9): p. 919-23.
13.O'Rourke, R.W., Inflammation in obesity-related diseases. Surgery, 2009. 145(3): p. 255-9.
14.Fantuzzi, G., Adipose tissue, adipokines, and inflammation. J Allergy Clin Immunol, 2005. 115(5): p. 911-9; quiz 920.
15.Tilg, H. and A.R. Moschen, Adipocytokines: mediators linking adipose tissue, inflammation and immunity. Nat Rev Immunol, 2006. 6(10): p. 772-83.
16.Schenk, S., M. Saberi, and J.M. Olefsky, Insulin sensitivity: modulation by nutrients and inflammation. J Clin Invest, 2008. 118(9): p. 2992-3002.
17.Kintscher, U., et al., T-lymphocyte infiltration in visceral adipose tissue: a primary event in adipose tissue inflammation and the development of obesity-mediated insulin resistance. Arterioscler Thromb Vasc Biol, 2008. 28(7): p. 1304-10.
18.Lumeng, C.N., J.L. Bodzin, and A.R. Saltiel, Obesity induces a phenotypic switch in adipose tissue macrophage polarization. J Clin Invest, 2007. 117(1): p. 175-84.
19.Zeyda, M., et al., Human adipose tissue macrophages are of an anti-inflammatory phenotype but capable of excessive pro-inflammatory mediator production. Int J Obes (Lond), 2007. 31(9): p. 1420-8.
20.Gerhardt, C.C., et al., Chemokines control fat accumulation and leptin secretion by cultured human adipocytes. Mol Cell Endocrinol, 2001. 175(1-2): p. 81-92.
21.Kanda, H., et al., MCP-1 contributes to macrophage infiltration into adipose tissue, insulin resistance, and hepatic steatosis in obesity. J Clin Invest, 2006. 116(6): p. 1494-505.
22.Coppack, S.W., Adipose tissue changes in obesity. Biochem Soc Trans, 2005. 33(Pt 5): p. 1049-52.
23.Nadler, S.T., et al., The expression of adipogenic genes is decreased in obesity and diabetes mellitus. Proc Natl Acad Sci U S A, 2000. 97(21): p. 11371-6.
24.Gustafson, B., et al., Inflammation and impaired adipogenesis in hypertrophic obesity in man. Am J Physiol Endocrinol Metab, 2009.
25.Cawthorn, W.P., et al., Tumour necrosis factor-alpha inhibits adipogenesis via a beta-catenin/TCF4(TCF7L2)-dependent pathway. Cell Death Differ, 2007. 14(7): p. 1361-73.
26.Helmersson, J., et al., Association of type 2 diabetes with cyclooxygenase-mediated inflammation and oxidative stress in an elderly population. Circulation, 2004. 109(14): p. 1729-34.
27.Liu, T.T., et al., Importance of cyclooxygenase 2-mediated low-grade inflammation in the development of fructose-induced insulin resistance in rats. Chin J Physiol, 2009. 52(2): p. 65-71.
28.Hsieh, P.S., et al., COX-2-mediated inflammation in fat is crucial for obesity-linked insulin resistance and fatty liver. Obesity (Silver Spring), 2009. 17(6): p. 1150-7.
29.Fain, J.N., L.R. Ballou, and S.W. Bahouth, Obesity is induced in mice heterozygous for cyclooxygenase-2. Prostaglandins Other Lipid Mediat, 2001. 65(4): p. 199-209.
30.Yokota, T., et al., Paracrine regulation of fat cell formation in bone marrow cultures via adiponectin and prostaglandins. J Clin Invest, 2002. 109(10): p. 1303-10.
31.Yan, H., et al., Role of cyclooxygenases COX-1 and COX-2 in modulating adipogenesis in 3T3-L1 cells. J Lipid Res, 2003. 44(2): p. 424-9.
32.Fajas, L., et al., Selective cyclo-oxygenase-2 inhibitors impair adipocyte differentiation through inhibition of the clonal expansion phase. J Lipid Res, 2003. 44(9): p. 1652-9.
33.Zhang, Y., et al., Positional cloning of the mouse obese gene and its human homologue. Nature, 1994. 372(6505): p. 425-32.
34.Considine, R.V., et al., Serum immunoreactive-leptin concentrations in normal-weight and obese humans. N Engl J Med, 1996. 334(5): p. 292-5.
35.Otero, M., et al., Towards a pro-inflammatory and immunomodulatory emerging role of leptin. Rheumatology (Oxford), 2006. 45(8): p. 944-50.
36.Matarese, G., et al., Balancing susceptibility to infection and autoimmunity: a role for leptin? Trends Immunol, 2002. 23(4): p. 182-7.
37.Raso, G.M., et al., Leptin potentiates IFN-gamma-induced expression of nitric oxide synthase and cyclo-oxygenase-2 in murine macrophage J774A.1. Br J Pharmacol, 2002. 137(6): p. 799-804.
38.Lappas, M., M. Permezel, and G.E. Rice, Leptin and adiponectin stimulate the release of proinflammatory cytokines and prostaglandins from human placenta and maternal adipose tissue via nuclear factor-kappaB, peroxisomal proliferator-activated receptor-gamma and extracellularly regulated kinase 1/2. Endocrinology, 2005. 146(8): p. 3334-42.
39.Elimam, A., A. Kamel, and C. Marcus, In vitro effects of leptin on human adipocyte metabolism. Horm Res, 2002. 58(2): p. 88-93.
40.Ramsay, T.G., Porcine preadipocyte proliferation and differentiation: a role for leptin? J Anim Sci, 2005. 83(9): p. 2066-74.
41.Wang, M.Y., et al., Fat storage in adipocytes requires inactivation of leptin's paracrine activity: implications for treatment of human obesity. Proc Natl Acad Sci U S A, 2005. 102(50): p. 18011-6.
42.Qian, H., et al., Down-regulation of CCAAT/enhancer binding proteins alpha, beta and delta in adipose tissue by intracerebroventricular leptin in rats. Biochim Biophys Acta, 1998. 1442(2-3): p. 245-51.
43.Bjorbaek, C., et al., The role of SOCS-3 in leptin signaling and leptin resistance. J Biol Chem, 1999. 274(42): p. 30059-65.
44.Schwartz, M.W., et al., Evidence that plasma leptin and insulin levels are associated with body adiposity via different mechanisms. Diabetes Care, 1997. 20(9): p. 1476-81.
45.Fain, J.N., et al., Stimulation of leptin release by arachidonic acid and prostaglandin E(2) in adipose tissue from obese humans. Metabolism, 2001. 50(8): p. 921-8.
46.Fain, J.N., C.W. Leffler, and S.W. Bahouth, Eicosanoids as endogenous regulators of leptin release and lipolysis by mouse adipose tissue in primary culture. J Lipid Res, 2000. 41(10): p. 1689-94.
47.Fain, J.N., et al., Regulation of leptin release and lipolysis by PGE2 in rat adipose tissue. Prostaglandins Other Lipid Mediat, 2000. 62(4): p. 343-50.
48.Kamei, N., et al., Overexpression of monocyte chemoattractant protein-1 in adipose tissues causes macrophage recruitment and insulin resistance. J Biol Chem, 2006. 281(36): p. 26602-14.
49.Rausch, M.E., et al., Obesity in C57BL/6J mice is characterized by adipose tissue hypoxia and cytotoxic T-cell infiltration. Int J Obes (Lond), 2008. 32(3): p. 451-63.
50.Curat, C.A., et al., From blood monocytes to adipose tissue-resident macrophages: induction of diapedesis by human mature adipocytes. Diabetes, 2004. 53(5): p. 1285-92.
51.Bays, H.E., et al., Pathogenic potential of adipose tissue and metabolic consequences of adipocyte hypertrophy and increased visceral adiposity. Expert Rev Cardiovasc Ther, 2008. 6(3): p. 343-68.
52.Chiba, T., et al., Leptin deficiency suppresses progression of atherosclerosis in apoE-deficient mice. Atherosclerosis, 2008. 196(1): p. 68-75.
53.Tamura, Y., et al., Inhibition of CCR2 ameliorates insulin resistance and hepatic steatosis in db/db mice. Arterioscler Thromb Vasc Biol, 2008. 28(12): p. 2195-201.