非酒精性脂肪性肝炎（NASH）建模专题
♦ 蛋氨酸/胆碱缺乏饲料(MCD，methionine -choline deficient diet)
♦ 高脂饲料（HFD，high-fat diet）
► 背 景
非酒精性脂肪性肝病（NAFLD）是全世界范围内最普遍的一种肝脏疾病和肝功能检测异常的最常见诱因，包含一系列的疾病状态。从最初单纯的脂肪变性（肝硬化）发展至病理性的非酒精性肝炎（Nonalcoholic steatohepatitis, NASH），进一步引起肝纤维化，甚至导致肝硬化、肝功能衰竭和肝癌等终末期肝病。NASH的发病常常与肥胖症、胰岛素抵抗、线粒体功能异常、II型糖尿病等相关。作为严重肝病发生的必经阶段，对NASH发病机制的认识和治疗极具重要性。
目前对NASH发病机制和评估治疗成效的研究主要以合适的动物模型为平台。营养诱发动物模型（食物喂养法）是NASH动物模型建立最常用的方法。其中MCD（methionine-choline deficient diet）和HFD（high-fat diet）为诱导NASH的两种常见饲料，研究者可根据各个方法的成模特征、周期、动物类型等选择适宜的方法。
专题一 NASH动物模型（MCD法）
► 简 介
蛋氨酸/胆碱缺乏饲料（methionine-choline deficient diet, MCD）是最经典的建立NASH动物模型的方法，已经具有40多年的应用历史。一般选用啮齿类动物。是研究NASH疾病相关的炎症、氧化应激、线粒体损伤、肝纤维化的最佳建模方法。
Mpbio公司提供两种类型的MCD动物饲料，分别是粉末状（powder）和颗粒状（pellet）。另外还提供MCD对照饲料，与普通MCD饲料配方相同，只是在减少等量蔗糖的基础上，增加2 g/kg 氯化胆碱和3 g/kg DL-蛋氨酸。
► MCD配方
|
配 方(Composition) |
|
Sucrose |
455.3 gm |
L-Isoleucine |
8.2 gm |
|
Corn Starch |
200.0 gm |
L-Leucine |
11.1 gm |
|
Corn Oil |
100.0 gm |
L-Lysine Hydrochloride |
18.0 gm |
|
Alphacel Non-Nutritive Bulk |
30.0 gm |
L-Phenylalanine |
7.5 gm |
|
AIN 76 Mineral Mix |
35.0 gm |
L-Proline |
3.5 gm |
|
Dicalcium Phosphate |
3.0 gm |
L-Serine |
3.5 gm |
|
L-Alanine |
3.5 gm |
L-Threonine |
8.2 gm |
|
L-Arginine Hydrochloride |
12.1 gm |
L-Tryptophan |
1.8 gm |
|
L-Asparagine Monohydrate |
6.0 gm |
L-Tyrosine |
5.0 gm |
|
L-Aspartic Acid |
3.5 gm |
L-Valine |
8.2 gm |
|
L-Cystine |
3.5 gm |
DL-alpha-Tocopherol Acetate (250 u/gm) |
0.484 gm |
|
L-Glutamic Acid |
40.0 gm |
Vitamin A Palmitate (250,000 u/gm) |
0.0792 gm |
|
Glycine |
23.3 gm |
Vitamin D3 (400,000 u/gm) |
0.0055 gm |
|
L-Histidine Hydrochloride |
4.5 gm |
Ethoxyquin |
0.02 gm |
|
Vitamin Mix |
|
Biotin |
0.0004 gm |
Pyridoxine Hydrochloride |
0.0220 gm |
|
D-Calcium Pantothenate |
0.0661 gm |
Riboflavin |
0.022 gm |
|
Folic Acidm |
0.002 g |
Thiamine Hydrochloride |
0.022 gm |
|
Inositol |
0.1101 gm |
Vitamin B12 (0.1% trit.) |
0.0297 gm |
|
Menadione |
0.0496 gm |
Ascorbic acid |
1.0166 gm |
|
Niacin |
0.0991 gm |
Corn Starch |
3.4503 gm |
|
p-Aminobenzoic Acid |
0.1101 gm |
|
|
► MCD订购信息
|
产品名称 |
货号 |
规格 |
产品形式 |
目录价 |
|
methionine-choline deficient diet（MCD） |
0296043810 |
10 kg |
powder |
9946.00 |
|
0296043910 |
10 kg |
pellet |
10170.00 |
|
methionine-choline deficient（MCD）,
control diet |
0296044010 |
10 kg |
powder |
9946.00 |
|
0296044110 |
10 kg |
pellet |
10170.00 |
► 应用文献
1. Emmanuel Mas etc., IL-6 Deficiency Attenuates Murine Diet-Induced Non-Alcoholic Steatohepatitis.
2. Christer Baeck etc., Pharmacological inhibition of the chemokine CCL2 (MCP-1) diminishes liver macrophage infiltration and steatohepatitis in chronic hepatic injury.
3. Yami Shapira etc.,Utilization of Murine Laparoscopy for Continuous In-VivoAssessment of the Liver in Multiple Disease Models.
4. Miao-Miao Fu etc., Increased susceptibility to experimental steatohepatitis induced by methionine-choline
deficiency in HBs-Tg mice. Hepatobiliary Pancreat Dis Int 2010; 9: 513-519.
5. Otto Kučera etc., The effect of rat strain, diet composition and feeding period on the development of a nutritional model of non-alcoholic fatty liver disease in rats.
6. Leclercq, I.A. etc., CYP2E1 and CYP4A as microsomal catalysts of lipid peroxides in murine nonalcoholic steatohepatitis. The Journal of Clinical Investigation,v. 10(8), 1067-1075.
专题二 NASH动物模型（HFD法）
► 简 介
除了MCD法，HFD(high-fat diet)法用于诱导动物脂肪变性和NASH的应用也十分普遍。因为与MCD法诱导的NASH动物模型相比，HFD诱导的NASH模型在发病机制上更相似于人NASH。经诱导的啮齿类动物呈现出体重增加，体内脂肪水平提高以及胰岛素抵抗等特征。HFD法诱导大鼠NASH模型的结果最为可信。研究显示，Sprague-Dawley大鼠喂养6周后患肥胖症，表现出ALT异常、脂肪肝、炎症、高脂血症、高胰岛素血症、高血糖症及IR等体征，另外喂养3周后动物体重和血浆ALT水平不会提高。总而言之，HFD诱导的NASH动物模型在脂肪变性、炎症和纤维化几个方面表现出个体上的差异，主要受动物种类、饲料中脂肪成分、饲料组成和喂养时间相关。
Research Diets公司提供两种类型的HFD动物饲料（45% kcal% fat.），分别有粉末状（powder）和颗粒状（pellet）。另外还提供LFD对照饲料（10% kcal% fat），方便客户监控造模的成功性及观察动物模型体内相关指标的变化。
► 高脂饲料（HFD）配方
|
HFD fomulation（total：4.73 kcal/gm） |
LFD fomulation（total：3.85 kcal/gm） |
|
成分 |
重量（gm） |
能量（kcal） |
成分 |
重量（gm） |
能量（kcal） |
|
Casein, 80 Mesh |
200 |
800 |
Casein, 80 Mesh |
200 |
800 |
|
L-Cystine |
3 |
12 |
L-Cystine |
3 |
12 |
|
Corn Starch |
72.8 |
291 |
Corn Starch |
315 |
1260 |
|
Maltodextrin |
100 |
400 |
Maltodextrin 10 |
35 |
140 |
|
Sucrose |
172.8 |
691 |
Sucrose |
350 |
1400 |
|
Cellulose, BW200 |
50 |
0 |
Cellulose, BW200 |
50 |
0 |
|
Soybean Oil |
25 |
225 |
Soybean Oil |
25 |
225 |
|
Lard* |
177.5 |
1598 |
Lard* |
20 |
180 |
|
Mineral Mix S10026 |
10 |
0 |
Mineral Mix S10026 |
10 |
0 |
|
DiCalcium Phosphate |
13 |
0 |
DiCalcium Phosphate |
13 |
0 |
|
Calcium Carbonate |
5.5 |
0 |
Calcium Carbonate |
5.5 |
0 |
|
Potassium Citrate,
1 H2O |
16.5 |
0 |
Potassium Citrate,
1 H2O |
16.5 |
0 |
|
Vitamin Mix V10001 |
10 |
40 |
Vitamin Mix V10001 |
10 |
40 |
|
Choline Bitartrate |
2 |
0 |
Choline Bitartrate |
2 |
0 |
|
FD&C Red Dye #40 |
0.05 |
0 |
FD&C Red Dye #40 |
0.05 |
0 |
|
Total |
858.15 |
4057 |
Total |
1055.05 |
4057 |
|
*Typical analysis of cholesterol in lard = 0.95 mg/gram.
Cholesterol (mg)/4057 kcal = 168.6
Cholesterol (mg)/kg = 196.5 |
*Typical analysis of cholesterol in lard = 0.95 mg/gram.
Cholesterol (mg)/4057 kcal= 19
Cholesterol (mg)/kg = 18 |
► 高脂饲料（HFD）订购信息
► 看看您需要pellet还是powder形式的产品？
|
Pellets |
Powder |
|
Pellets are easier to feed than powder. Pellets can simply be thrown on top of the cage or even inside. Its easy to monitor the pellet supply and assure that animals have 24/7 access to feed. |
Powder requires special feeders. The feeders can be easily tipped and spilled, and the food can also be easily soiled by urine, feces or even saliva. So it is difficult to assure that the animals have 24/7 access to good clean food. |
|
Pellets are a stable food stuff. They can be stored for months without losing quality. |
Powder has much greater surface area and the food spoils much easier. Powder also has a less obvious problem in as much as powders can become ‘unmixed’ over time. That is, smaller, more dense particles may sift to the bottom and less dense, fluffier parts may sift up, making the diet no longer homogenous and in the extreme nutritionally incomplete from top or bottom. |
|
Pellets are homogeneous. |
Powder can be separated by the animal by pawing, sniffing and snorting, either intentionally or inadvertently. |
|
Once pelleted compounds are ‘frozen’ in place and won’t become unmixed. Also the test compound is more stable in pellets as most of it is inside the pellet and away from direct air, light and humidity which cause most of the degradation of test compounds. |
Powder is often used by facilities that lack the equipment, personnel, money or interest in pelleting food. This is often done when researchers want to add test compounds to feed. Test compounds can easily sift out of the powder. |
|
Pellets are dustless and cannot be inhaled. |
Powder can be (or is) inhaled by feeding animals causing respiratory irritation and infections. This is an often overlooked problem with feeding powder diets. This is especially likely with powders of standard chows, which unless irradiated are loaded with microbes. |
|
Feeding pellets helps ‘wear’ incisors down. |
Powder fed rodents may develop overgrown incisors |
