论文部分内容阅读
AIM:To characterize an alcohol and high fat diet induced chronic pancreatitis rat model that mimics poor human dietary choices.METHODS:Experimental rats were fed a modified Lieber-De Carli alcohol(6%) and high-fat(65%) diet(AHF) for 10 wk while control animals received a regular rodent chow diet.Weekly behavioral tests determinedmechanical 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.Insulinexpressing 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).RESULTS: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/d L in controls vs 161.0 ± 8.6 mg/d L,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.Hypersensitivitywas 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.CONCLUSION:The AHF diet induces a chronic alcoholic pancreatitis in rats with measurable features resembling clinical patients with chronic pancreatitis and type 3c diabetes mellitus.
AIM: To characterize an alcohol and high fat diet induced chronic pancreatitis rat model that mimics poor human dietary choices. METHODS: Experimental rats were fed a modified Lieber-De Carli alcohol (6%) and high-fat (65%) diet ) for 10 wk while control animals received a regular rodent chow diet. Weekly behavioral tests determined mechanism and heat sensitivity. Week 10 a fasting glucose tolerance test was performed, measuring blood glucose levels before and after a 2 g / kg bodyweight intraperitoneal (ip) 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 xpressing 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 dr ugs 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, (20,60,200 nmol / kg, ip; Tocris), and morphine sulfate (3 mg / kg, μ-opioid receptor agonist; Baxter Healthcare, Deerfield, IL, United States) .RESULTS: 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% 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 / d L, P < 0.05). This concurred with a 3.5 fold higher incidence of single and small 2-10 cell insulin- positiverophic expression islet of Langerhans cells were hypertrophy while islet number and area measurements were not from from controls. Weekly behavioral tests determined that mechanical and heat sensitivities were significantly increased by 4 weeks on AHF diet compared to controls . Hypersensitivity was attenuated with effector 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. CONCLUSION: The AHF diet induces a chronic alcoholic pancreatitis in rats with measurable features resembling clinical patients with chronic pancreatitis and type 3c diabetes mellitus.