Effects of Time-Restricted and Alternate- Day Intermittent Fasting on Liver Enzymes, Glycogen and Oral Glucose Tolerance Test in Streptozotocin-induced Diabetic Rats

Intermittent fasting (IF) has been reported to improve metabolic health in diabetes but the underlying mechanisms by which intermittent fasting promotes metabolic health in streptozotocin-induced diabetes have not been fully elucidated. This study investigated the effects of Time-Restricted (TR) and Alternate- Day (AD) Intermittent Fasting (IF) on body weight, liver enzymes, liver glycogen, blood glucose, and oral glucose tolerance test (OGTT) in streptozotocin-induced diabetic male Wistar rats. Sixty male Wistar rats (200-250g) were grouped into six groups (n=10). Group 1 (non-diabetic control) and Group 2 (non-diabetic +time-restricted intermittent fasting). Groups 3 - 6 received streptozotocin (50mg/kg) intraperitoneally (i.p.). After diabetes was confirmed, animals in groups 3, 5 and 6 were treated with Time-restricted intermittent fasting, metformin (200mg/kg) orally, and Alternate- day intermittent fasting protocols respectively, while group 4 animals were untreated (Diabetic control) for 28days. After 28 days, oral glucose tolerance test (OGTT), fasting blood glucose (FBG), liver function enzymes, Aspartate Aminotransferase (AST), Alanine Transaminase (ALT), and Alkaline Phosphatase (ALP) were measured. The results showed that while there was significant decrease in body weight, there was significant increase in fasting blood glucose and concentrations of liver enzymes AST, ALT and ALP in group 4 compared to group 1. Time- restricted fasting, metformin treatment and Alternate day intermittent fasting caused significant decrease in body weight, fasting blood glucose and serum levels of AST, ALT and ALP in groups 3, 5 and 6 compared to group 4. Liver glycogen was significantly reduced in group 4 and increased in groups 3, 5 and 6 of diabetic rats. The study showed that Time-restricted (18: 6) and Alternate-Day intermittent fasting regimens ameliorated diabetes through improved glucose tolerance, liver glycogen synthesis and liver function enzymes.