Retrieval of Normal Sleep for Two Weeks Normalized Adiposity and Minimized Insulin Resistance Induced by 4-Week Insomnia in Aged Female Rats
Authors: Samy A , Mohamed N , Ibrahim G , Mohamed I 
Published: November 2024

Abstract

Background
Insomnia affects the energy metabolism components which may alter the body’s metabolic functions. Sleep disturbances, both quantitative and qualitative, may increase the risk of developing chronic conditions, such as obesity, metabolic disorders, diabetes, and cardiovascular disease.

Aim
This study was carried out to investigate the effect of insomnia on glucose homeostasis in aged female rats, and to elucidate the possible underlying mechanism(s), as well as the potential metabolic recovery after retrieval to the normal sleep pattern.

Methods
60 Sprague Dawley aged female rats were randomly divided into two main groups: Control group (C) and Insomnia group (I). The latter was further subdivided into two subgroups, 10 rats each: Group Iins. which was subjected to insomnia four hours daily, five days /week for 4 weeks, and Group Іins, Rec. that was subjected to insomnia like Iins. group with retrieval to normal sleep for two weeks. Rats in all groups were subjected to estimation of Body weight (BW), Body mass index (BMI) and Waist circumference at the beginning of the study. The intraperitoneal glucose tolerance test (IPGTT) was measured at the beginning of the study and was monitored every two weeks. By the end of fourth week (for groups C and Iins.) & By the end of the sixth week (for group Iins.rec). BW, BMI, Waist circumference, intraperitoneal glucose tolerance test (IPGTT), peak glycemia (PG) and area under the curve (AUC), Fasting blood glucose (FBG), Insulin, Homeostatic Model Assessment for Insulin Resistance (HOMA- IR), Total cholesterol (TC), Triglycerides (TG), Low density lipoprotein cholesterol (LDL-C), High density lipoprotein cholesterol (HDL-C), Adiponectin, IL6 and Caspase 3 were estimated.

Results
After four weeks, Iins. rats exhibited a significantly higher change in BW, BMI, WC, FBG, blood glucose levels at 30 min., 60 min, 90 min., 120 min, PG and AUC of IPGGT, insulin level and HOMA-IR, serum (TGs), (TC), (LDL-C), serum IL6 & caspase3 but showed significant decrease in serum level of (HDL-C) and adiponectin in comparison to C rats, After two week recovery from insomnia, Iins.rec. rats exhibited a significantly lower values of WC, FBG, insulin, HOMA-IR, (TGs), (TC), (LDL-C), serum IL6 & caspase3 with insignificant change in BW, BMI, blood glucose levels at 30 min., 60 min, 90 min., 120 min, PG, AUC of IPGGT & serum (HDL-C) with significantly higher values of adiponectin when compared to Iins.rats, and exhibited insignificant change in BW, BMI, WC, FBG, blood glucose levels at 60 min. and at 90 min, (TC), (LDL-C) and adiponectin with significantly higher values of blood glucose levels at 30 min., 120 min, PG and AUC of IPGGT insulin level, HOMA-IR, serum (TGs), serum IL6 & caspase3 with significantly lower values serum (HDL-C) in comparison to the C rats.

Conclusion
Four-week insomnia in aged female rats resulted in increased blood glucose, insulin resistance, dyslipidemia and enhanced inflammatory and apoptotic states. Retrieval of normal sleep for two weeks normalized body adiposity, fasting blood glucose, total cholesterol and LDL-C and minimized the insulin resistance, hypertriglyceridemia and the decrease in HDL-C as well as inflammation and apoptosis.