EXPERIMENTAL RESEARCH
Comparing prophylactic effect of exercise and metformin on cognitive brain functions in rats with type 3 diabetes mellitus
 
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1
Department of Medical Physiology, Kasr Alainy Faculty of Medicine, Cairo University, Egypt
2
Department of Biochemistry, Faculty of Medicine, Cairo University, Egypt
3
Department of Anatomy and Embryology, Faculty of Medicine, Assiut University, Egypt
4
Department of Histology and Cytology, Faculty of Medicine, Alazhar University, Egypt
5
Department of Pathology and Laboratory Medicine, VAMC North East Ohio Healthcare System, Louis Stokes, Cleveland, Ohio, USA
Submission date: 2019-07-29
Final revision date: 2020-03-10
Acceptance date: 2020-03-26
Online publication date: 2020-09-16
 
 
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ABSTRACT
Introduction:
Type 2 diabetes mellitus (DM) and Alzheimer’s disease (AD) are two major medical conditions that constitute a significant financial burden on most healthcare systems. Due to AD sharing “insulin resistance” mechanistic features with DM, some scientists have proposed “type 3 DM” terminology for it. This study aims to compare the prophylactic effect of exercise and metformin on cognitive brain functions in rats with type 3 DM.

Material and methods:
Two groups of rats were included in the study: the control group (n = 15) and the streptozotocin-induced type 2 diabetic group (n = 45). The diabetic group was subdivided into three equal subgroups: a sedentary non-treated diabetic group, an exercised group, and a metformin-treated group. We estimated step-down avoidance task latency, serum glucose, insulin, free fatty acids (FFA), cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides (TG), brain A-42 and glucose, histological changes by toluidine blue, and immunohistochemistry for brain Aβ-42 and tau-positive cells.

Results:
Serum glucose, FFA, TG, cholesterol, LDL, brain Aβ-42, brain glucose, the number of hippocampal dark and degenerated cells, and brain Aβ-42 and tau-positive cells, were all significantly lower. In contrast, serum insulin and HDL, the number of hippocampal granular cells, and latency of the step-down avoidance task were significantly higher in exercised and metformin-treated groups compared to the diabetic group. There were significantly higher values of serum insulin and brain/plasma glucose ratio and number of brain tau-positive cells in the metformin-treated group than in the exercised group.

Conclusions:
We can conclude that exercise can be as effective as metformin regarding prophylaxis against the deleterious effects of type 3 DM on cognitive brain functions.

eISSN:1896-9151
ISSN:1734-1922