Effects Of Acute Exercise And Fasting On Liver Glycogen Content And Glycoconjugate In Nafld Mice

Objective: Nonalcoholic fatty liver disease (NAFLD) is often associated with abnormal regulation of liver glycogen metabolism and gluconeogenesis.The purpose of this study was to investigate the effects of acute exercise and fasting on liver glycogen content and gluconeogenesis in NAFLD mice. METHODS: C57BL / 6 J mice were fed a normal diet and a high-fat, fructose and cholesterol(HFFC)diet for 12 weeks, and then they were equally divided into four groups (n = 8 each): Normal Diet (ND), HFFC diet control (HC), HFFC diet with 24 hours fasting (HF), and HFFC diet with 8 weeks Exercise (HE) (n = 8). At the end of the experiment, fasting blood glucose and liver glycogen content were measured and the activity and protein expression level of hepatic gluconeogenesis key proteins (G-6-P, PEPCK) were detected. RESULTS:1 ) Mice in the HC group showed a significant increase in fasting blood glucose (15.27 ± 2.59 vs 25.64 ± 5.31 mmol/L) compared to ND group mice. Both 24-hour fasting (8.68 ± 2.94 mmol/L) and acute exercise (20.54 ± 5.41 mmol/L) significantly decreased the fasting blood glucose compared with the HC group (P < 0.05). 2 ) Compared to the ND group, the glycogen content ( 7.29 ± 1.25 vs 9.91 ± 2.33 mg / g ) and glycogen staining area ( 69.02 ± 5.58 vs 86.46 ± 4.54 % ) in HC group were significantly increased. However, compared with the HC group, mice in both HF and HE groups showed marked drop in the glycogen content ( 4.37 ± 0.85 mg / g, 4.14 ± 0.81 mg / g) and the staining area ( 52.75 ± 11.63 %, 51.73 ± 10.35 % ) ( P < 0.05 ).3 ) 24 hours fasting resulted in notably increased in G-6-P activity ( 63.08 ± 10.56 vs 84.43 ± 5.07 U / mg ) ( P < 0.05 ), G-6-P (0.48 ± 0.21 vs 1.23 ± 0.42 ) and PEPCK (0.28 ± 0.16 vs 0.97 ± 0.64 ) protein expression level( P < 0.05 ), while acute exercise did not change G-6-P and PEPCK activities and expressions in HFFC diet mice. CONCLUSION: 1 ) 12-week HFFC diet remarkably increased blood glucose and liver glycogen levels.2 ) 24-hour fasting significantly reduced blood glucose levels in NAFLD mice, accompanied by increased levels of hepatic glycogen breakdown and gluconeogenesis.3 ) Acute exercise leads to a decrease in blood glucose levels and an increase in hepatic glycogen breakdown in NAFLD mice, but do not alter hepatic gluconeogenesis. Keywords: nonalcoholic fatty liver disease, fasting, acute exercise, gluconeogenesis Supported by: This work was supported by the Higher Education Institutions in Jiangsu Province (24KJA310002), Youth Project of National Natural Science Foundation of China (32000839), Graduate Research and Innovation Projects of Jiangsu Province(KYCX23_2363).