Lipid Fatty Acid Profile Analyses in Liver and Serum in Rats with Nonalcoholic Steatohepatitis Using Improved Gas Chromatography−Mass Spectrometry Methodology

• Published in: Journal of agricultural and food chemistry 2011-01, Vol.59 (2), p.747-754
• Main Authors: Wu, Xianli, Tong, Yudong, Shankar, Kartik, Baumgardner, January N, Kang, Jie, Badeaux, Jamie, Badger, Thomas M, Ronis, Martin J.J
• Format: Article
• Language: English
• Subjects: animal models; Animals; Biological and medical sciences; blood serum; corn oil; diet; enteral feeding; fatty acid composition; Fatty Acids - blood; Fatty Acids - metabolism; Fatty Liver - blood; Fatty Liver - metabolism; fibrosis; Food Chemistry/Biochemistry; Food industries; free fatty acids; Fundamental and applied biological sciences. Psychology; gas chromatography; Gas Chromatography-Mass Spectrometry - methods; hepatitis; Humans; inflammation; linoleic acid; liver; Liver - chemistry; Liver - metabolism; Male; mass spectrometry; methylation; necrosis; new methods; Non-alcoholic Fatty Liver Disease; overfeeding; phospholipids; Random Allocation; Rats; Rats, Sprague-Dawley; transesterification; triacylglycerols
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf1038426

Fatty acids (FAs) are essential components of lipids and exhibit important biological functions. The analyses of FAs are routinely carried out by gas chromatography−mass spectrometry after multistep sample preparation. In this study, several key experimental factors were carefully examined, validated, and optimized to analyze free fatty acid (FFA) and FA profiles of triglycerides and phospholipids in serum or tissue samples. These factors included (1) methylation/transesterification reagents, (2) validation of internal standards, and (3) final step concentration of FA methyl esters. This new method was utilized to analyze FFAs and the FA profiles of triglycerides and phospholipids in the serum and liver from a recently established rat model of nonalcoholic steatohepatitis (NASH). In this model, rats were fed a 220 kcal kg −3/4 day −1 diet containing either 5 or 70% corn oil for 21 days using total enteral nutrition. FA compositions of the serum and liver were found to shift from a pattern dominated by saturated and monounsaturated FAs (C16:0/18:1) to one dominated by polyunsaturated C18:2 derived from dietary linoleic acid. Alteration of FA composition in liver after overfeeding of high polyunsaturated fat diets may contribute to the progression of pathological changes from steatosis to inflammation, necrosis, and fibrosis observed in NASH.