The Possible Role of Interleukin 28 in Improvement of Liver Functions in Exercise-Treated High Fructose Fed Rats

Background: Consumption of dietary fructose has been suggested to be one of the environmental factors contributing to the development of obesity, diabetes, dyslipidemia, and to a substantial decrease in both liver and muscle insulin sensitivity. Regular physical exercise is an important measure to prevent and treat the metabolic effects of high fructose diet. It exerts its anti inflammatory effect by inhibiting the release of proinflammatory cytokines and stimulating the release of anti inflammatory cytokins. Interleukin 28 is a novel cytokine. It is functionally an interferon but structurally it is related to the interleukin-10 family. Its anti-inflammatory effect may play a role in improving liver functions in high fructose fed rats. Material and Methods: In this study we aimed to investigate the impact of exercise on functional and histological features of liver in high fructose fed rats and to elucidate its effect on the expression of interleukin 28 in liver tissues of these rats. Twenty seven male albino rats were used in this study. Animals were divided into three equal groups: Control group, fructose group: Rats in this group were fed a 66% fructose diet to induce development of the metabolic syndrome, Exercise-treated group: Rats in this group were fed a 66% fructose diet and submitted at same time to swimming exercise. After 28 days animals were weighed then sacrificed by cervical decapitation. Blood samples were taken for estimation of fasting serum glucose, lipids, uric acid and liver enzymes alanine aminotranseferase (ALT) and aspartate aminotranseferase (AST). Fresh livers were excised, for formation of liver homogenate and embedded paraffin blocks for immuno-histopathological examination. Liver homogenates were used to estimate the level of lactate, pyruvate and calculate lactate/ pyruvate ratio. Results: High fructose diet significantly increased body weight, fasting serum glucose and lipids, uric acid and liver enzymes. The livers in this group showed significant increase in ischak score of necrofibrosis. Exercise treatment significantly decreased body weight, fasting serum glucose and lipids, uric acid and liver enzymes. Livers in this group showed significant decrease in ischak score of necrofibrosis and significant increase in expression of interleukin 28.