Effect of Caloric Restriction on Renal Function in a Rat Model of High Fat Diet Induced Obesity
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- Category: Vol. 85, December 2017
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Effect of Caloric Restriction on Renal Function in a Rat Model of High Fat Diet Induced Obesity, ABD EL-AZIZ A. DIAB, ALI KH. ASALA, AHMED A. HENDAWY, SUZAN M.M. MOURSI and MOHAMED M. SHABAN
Abstract
Background: Obesity is as a serious health issue that may cause a change in the renal hemodynamics that promotes progressive kidney disease. Excess lipid accumulation leads to lipotoxicity and may be the major cause for organ dysfunc-tion. Increased knowledge of the link between obesity and kidney function will allow for novel therapeutic approaches to prevent obesity-induced kidney injury.
Objective: This study was designed to investigate the effects of high fat diet induced obesity and caloric restriction on renal structure and function and to determine the possible mechanisms in a rat model.
Material and Methods: Thirty healthy adult male albino rats were used for this study. The rats were randomly and equally divided into three groups. Group-1 normal diet (5% of energy derived from fat, 18% from proteins, and 77% from carbohydrates; 3.3kcal/g) fed control group, Group-2 obese rats in which obesity was induced by High Fat Diet (HFD) (58% of energy derived from fat, 18% from protein, and 24% from carbohydrates; 5.6kcal/g) for 16 weeks and Group-3 fed on high fat diet for 16 weeks then followed by diet restriction by feeding normal diet for 8 weeks. Rats were examined for body weight, Body Mass Index (BMI), Abdominal Circum-ference (AC), serum glucose and insulin, insulin resistance, lipids profile, serum leptin, resistin, Adiponectin (ADP), lipocalin-2 and inflammatory cytokines [Interleukin-6 (IL-6), Tumer Necrosis Factor-alpha (TNF-a), C-Reactive Protein (CRP) and Plasminogen Activator Inhibitor-1 (PAI-1)], serum urea, creatinine, uric acid and angiotensin II, systolic blood pressure, urine flow rate, protein and creatinine and Glomerular Filtration Rate (GFR). Histopathological examination for renal tissue was also evaluated.
Results: The present study revealed that obesity signifi-cantly increased body weight, BMI and abdominal circumfer-ence, serum glucose and insulin with insulin resistance, serum total cholesterol, triglyceride, Low Density Lipoproteins (LDLc) and Very Low Density Lipoproteins (VLDLc), serum leptin, resistin, IL-6, TNF-a, CRP and PAI-1, serum urea, creatinine, uric acid, angiotensin II and lipocalin-2 levels, systolic blood pressure, and urine flow rate and protein but significantly decreased urine creatinine, GFR, serum ADP and High Density Lipoproteins (HDLc) together with deteri-oration of renal histoarchitecture. Moreover, it was found that diet restriction resulted in a significant recovery of all the above-mentioned parameters in rats fed HFD followed by dietary restriction.
Conclusion: HFD induced obesity in rats is associated with Metabolic Syndrome (MS), low grade inflammation and altered adipocytes release of several adipocytokines. These hemodynamic, metabolic and biochemical changes may pre-dispose to structural, histopathologic and functional alterations in the kidney. Also, the present data indicate that many of the obesity associated disorders even the nephropathologic man-ifestation can be reversed or ameliorated with reduction in body fat and body weight induced by dietary energy restriction.