McIlwrath Sabrina L, Westlund Karin N
Sabrina L McIlwrath, Karin N Westlund, Department of Physiology, University of Kentucky, Lexington, KY 40536-0298, United States.
World J Gastroenterol. 2015 Jan 21;21(3):836-53. doi: 10.3748/wjg.v21.i3.836.
To characterize an alcohol and high fat diet induced chronic pancreatitis rat model that mimics poor human dietary choices.
Experimental rats were fed a modified Lieber-DeCarli alcohol (6%) and high-fat (65%) diet (AHF) for 10 wk while control animals received a regular rodent chow diet. Weekly behavioral tests determined mechanical and heat sensitivity. In week 10 a fasting glucose tolerance test was performed, measuring blood glucose levels before and after a 2 g/kg bodyweight intraperitoneal (i.p.) injection of glucose. Post mortem histological analysis was performed by staining pancreas and liver tissue sections with hematoxylin and eosin. Pancreas sections were also stained with Sirius red and fast green to quantify collagen content. Insulin-expressing cells were identified immunohistochemically in separate sections. Tissue staining density was quantified using Image J software. After mechanical and heat sensitivity became stable (weeks 6-10) in the AHF-fed animals, three different drugs were tested for their efficacy in attenuating pancreatitis associated hypersensitivity: a Group II metabotropic glutamate receptor specific agonist (2R,4R)-4-Aminopyrrolidine-2,4-dicarboxylate (APDC, 3 mg/kg, ip; Tocris, Bristol, United Kingdom), nociceptin (20, 60, 200 nmol/kg, ip; Tocris), and morphine sulfate (3 mg/kg, μ-opioid receptor agonist; Baxter Healthcare, Deerfield, IL, United States).
Histological analysis of pancreas and liver determined that unlike control rats, AHF fed animals had pancreatic fibrosis, acinar and beta cell atrophy, with steatosis in both organs. Fat vacuolization was significantly increased in AHF fed rats (6.4% ± 1.1% in controls vs 23.8% ± 4.2%, P < 0.05). Rats fed the AHF diet had reduced fasting glucose tolerance in week 10 when peak blood glucose levels reached significantly higher concentrations than controls (127.4 ± 9.2 mg/dL in controls vs 161.0 ± 8.6 mg/dL, P < 0.05). This concurred with a 3.5 fold higher incidence of single and small 2-10 cell insulin-positive cell clusters (P < 0.05). Insulin expressing islet of Langerhans cells appeared hypertrophied while islet number and area measurements were not different from controls. Weekly behavioral tests determined that mechanical and heat sensitivities were significantly increased by 4 wk on AHF diet compared to controls. Hypersensitivity was attenuated with efficacy similar to morphine with single dose treatment of either metabotropic glutamate receptor 2/3 agonist APDC, or nociceptin, the endogenous ligand for opioid-receptor-like 1 receptor.
The AHF diet induces a chronic alcoholic pancreatitis in rats with measurable features resembling clinical patients with chronic pancreatitis and type 3c diabetes mellitus.
建立一种模拟人类不良饮食选择的酒精和高脂饮食诱导的慢性胰腺炎大鼠模型。
将实验大鼠喂食改良的Lieber-DeCarli酒精（6%）和高脂（65%）饮食（AHF）10周，而对照动物给予常规啮齿动物饲料。每周进行行为测试以确定机械和热敏感性。在第10周进行空腹葡萄糖耐量试验，测量腹腔注射2g/kg体重葡萄糖前后的血糖水平。死后通过苏木精和伊红对胰腺和肝脏组织切片进行组织学分析。胰腺切片还用天狼星红和固绿染色以定量胶原含量。在单独的切片中通过免疫组织化学鉴定胰岛素表达细胞。使用Image J软件对组织染色密度进行定量。在AHF喂养的动物中机械和热敏感性稳定后（第6 - 10周），测试三种不同药物减轻胰腺炎相关超敏反应的疗效：II组代谢型谷氨酸受体特异性激动剂（2R,4R）-4-氨基吡咯烷-2,4-二羧酸（APDC，3mg/kg，腹腔注射；Tocris，英国布里斯托尔）、孤啡肽（20、60、200nmol/kg，腹腔注射；Tocris）和硫酸吗啡（3mg/kg，μ-阿片受体激动剂；百特医疗保健公司，美国伊利诺伊州迪尔菲尔德）。
胰腺和肝脏的组织学分析确定，与对照大鼠不同，AHF喂养的动物有胰腺纤维化、腺泡和β细胞萎缩，两个器官均有脂肪变性。AHF喂养的大鼠脂肪空泡化显著增加（对照组为6.4%±1.1%，而AHF组为23.8%±4.2%，P<0.05）。喂食AHF饮食的大鼠在第10周时空腹葡萄糖耐量降低，此时血糖峰值水平显著高于对照组（对照组为127.4±9.2mg/dL，而AHF组为161.0±8.6mg/dL，P<0.05）。这与单个和小的2 - 10细胞胰岛素阳性细胞簇的发生率高3.5倍一致（P<0.05）。表达胰岛素的胰岛细胞出现肥大，而胰岛数量和面积测量与对照组无差异。每周行为测试确定，与对照组相比，AHF饮食4周后机械和热敏感性显著增加。代谢型谷氨酸受体2/3激动剂APDC或孤啡肽（阿片受体样1受体的内源性配体）单剂量治疗可减轻超敏反应，疗效与吗啡相似。
AHF饮食可诱导大鼠发生慢性酒精性胰腺炎，其可测量特征类似于慢性胰腺炎和3c型糖尿病临床患者。
