Tryptophan Prevents the Development of Non-Alcoholic Fatty Liver Disease

Roman Yanko,1,* Mikhail Levashov,1,* Olena Georgievna Chaka,1 Valentina Nosar,1 Sergey G Khasabov,2 Iryna Khasabova2,* 1Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Kiev, Ukraine; 2Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA*These authors contributed equally to this workCorrespondence: Roman Yanko, Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Bogomoletz Street 4, Kiev, 01024, Ukraine, Tel +380442562477, Email biolag@ukr.netPurpose: The main aim of this research is to study the protective effects of tryptophan on the histomorphological and biochemical abnormalities in the liver caused by a high-calorie diet (HCD), as well as its ability to normalize mitochondrial functions in order to prevent the development of non-alcoholic fatty liver disease (NAFLD).Methods: The study was conducted in male Wistar rats aged 3 months at the start of the experiment. Control animals (group I) were fed a standard diet. Group II experimental animals were fed a diet with an excess of fat (45%) and carbohydrates (31%) for 12 weeks. Group III experimental animals also received L-tryptophan at a dose of 80 mg/kg body weight in addition to the HCD. The presence of NAFLD, functional activity, physiological regeneration, and the state of the liver parenchyma and connective tissue were assessed using physiological, morphological, histo-morphometric, biochemical, and biophysical research methods.Results: HCD induced the development of NAFLD, which is characterized by an increase in liver weight, hypertrophy of hepatocytes and an increase in the concentration of lipids, cholesterol and triglycerides in liver tissue. Increased alanine aminotransferase activity in the liver of obese rats also confirm hepatocytes damage. Tryptophan added to the diet lowered the severity of NAFLD by reducing fat accumulation and violations of bioelectric properties, and prevented a decrease in mitochondrial ATP synthesis.Conclusion: The addition of tryptophan can have a potential positive effect on the liver, reducing the severity of structural, biochemical, mitochondrial and bioelectric damage caused by HCD.Keywords: fatty liver disease, essential amino acids, obesit