Renal Changes (Structural and Functional) in The High Fat Diet-Induced Obesity and The Effect of Food Restriction: An Experimental Study

Abstract

Introduction and aim: Obesity is a worldwide epidemic and nearly affects every organ. However, the renal changes in obesity are not sufficiently addressed. Thus we aimed to investigate the effects of high-fat diet induced obesity on the kidney and explore the effect of caloric restriction on the renal changes associated with obesity.

Methodology: Thirty male albino rats, 160-180 g included and divided into three equal groups. The first is the control group (received nothing except normal diet). The second is the high fat diet-fed group, where rats fed on high fat diet for 12 weeks. The third group fed as the second one for 12 weeks followed by diet restriction for 6 weeks by feeding on normal chow diet. The following measurement were recorded: 1) Initial and final body weight, 2) serum value of different biochemical parameters (lipid profile, glucose, insulin, cytokines, inflammatory markers and renal function tests). Finally, kidney was extract, fixed and prepared for histopathological examination.

Results: The final weight significantly increased in the obese than the control and diet restriction groups (421.0±17.13 versus 279.50±11.17 and 333.0±13.33 g, successively). The total cholesterol, TG, LDL, vLDL, glucose, insulin, HOMA-IR, IL-6, leptin, resistin, TNF-α, CRP and Plasminogen activator inhibitor-1, creatinine, urea, protein in urine, uric acid were significantly higher in obese than control and diet-restriction groups. However, HDL and adiponectin were significantly reduced in obese than the control and diet restriction groups. The diet restriction significantly improved laboratory values, but it remains significantly different than the control group. The correlation between weight gain with other variables and renal structural changes confirmed the laboratory results.

Conclusion: Obesity is associated with functional and structural renal changes. The potential mechanisms involve inflammation, lipotoxicity and perhaps other unknown mechanisms. Weight reduction constitutes the most effective intervention to guard or treat obesity-associated chronic kidney disease.