A new model for nonalcoholic steatohepatitis in the rat utilizing total enteral nutrition to overfeed a high-polyunsaturated fat diet.

Abstract

We have used total enteral nutrition (TEN) to moderately overfeed rats high-polyunsaturated fat diets to develop a model for nonalcoholic steatohepatitis (NASH). Male Sprague-Dawley rats were fed by TEN a 187 kcal.kg(-3/4).day(-1) diet containing 5% (total calories) corn oil or a 220 kcal.kg(-3/4).day(-1) diet in which corn oil constituted 5, 10, 25, 35, 40, or 70% of total calories for 21 or 65 days. Rats fed the 5% corn oil, 220 kcal.kg(-3/4).day(-1)diet had greater body weight gain (P < or = 0.05), fat mass (P < or = 0.05), and serum leptin and glucose levels (P < or = 0.05), but no liver pathology. A dose-dependent increase in hepatic triglyceride deposition occurred with increase in percent corn oil in the 220 kcal.kg(-3/4).day(-1) groups (P < or = 0.05). Steatosis, macrophage infiltration, apoptosis, and focal necrosis were present in the 70% corn oil group, accompanied by elevated serum alanine aminotransferase (ALT) levels (P < or = 0.05). An increase in oxidative stress (thiobarbituric acid-reactive substances) and TNF-alpha expression (P < or = 0.05) was observed in the 70% corn oil group, as well as an increase in hepatic CYP2E1 and CYP4A1 expression (P < or = 0.05). Significant positive correlations were observed between the level of dietary corn oil and the degree of pathology, ALTs, oxidative stress, and inflammation. Liver pathology was progressive with increased necrosis, accompanied by fibrosis, observed after 65 days of TEN. Increased expression of CD36 and l-fabp mRNA suggested development of steatosis was associated with increased fatty acid transport. These data suggest that intragastric infusion of a high-polyunsaturated fat diet at a caloric level of 17% excess total calories results in pathology similar to clinical NASH.

• Authors: January N Baumgardner, Kartik Shankar, Leah Hennings, Thomas M Badger, Martin J J Ronis
• Journal: American journal of physiology. Gastrointestinal and liver physiology (Am J Physiol Gastrointest Liver Physiol) Vol. 294 Issue 1 Pg. G27-38 (Jan 2008) ISSN: 0193-1857 [Print] United States
• PMID: 17947452 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Blood Glucose
• CD36 Antigens
• Fatty Acid-Binding Proteins
• Fatty Acids
• Leptin
• RNA, Messenger
• Triglycerides
• Tumor Necrosis Factor-alpha
• Corn Oil
• Cytochrome P-450 CYP2E1
• Cytochrome P-450 CYP4A
• Alanine Transaminase

Topics

• Adiposity
• Alanine Transaminase (blood)
• Animals
• Apoptosis
• Blood Glucose (metabolism)
• Body Weight
• CD36 Antigens (analysis)
• Corn Oil (administration & dosage)
• Cytochrome P-450 CYP2E1 (biosynthesis)
• Cytochrome P-450 CYP4A (biosynthesis)
• Disease Models, Animal
• Enzyme Induction
• Fatty Acid-Binding Proteins (genetics, metabolism)
• Fatty Acids (metabolism)
• Fatty Liver (etiology, genetics, metabolism, pathology)
• Leptin (blood)
• Liver (enzymology, metabolism, pathology)
• Macrophages (pathology)
• Male
• Necrosis
• Overnutrition (complications, genetics, metabolism, pathology)
• Oxidative Stress
• Parenteral Nutrition, Total
• RNA, Messenger (metabolism)
• Rats
• Rats, Sprague-Dawley
• Time Factors
• Triglycerides (metabolism)
• Tumor Necrosis Factor-alpha (metabolism)