Pathophysiological analysis of the kidneys of obese type 2 diabetic model SDT fatty rats fed high-sucrose/high-fat diet and comparison between males and females

Abstract

　Type 2 diabetic model SDT fatty rats (SDTf rats) develop severe diabetes with obesity and male rats show severer phenotype compared to female rats. However, the effects of food on their kidney have not been reported. In this study, we investigated the effect of high-sucrose/high-fat diet (Quick fat; QF) on kidney of SDTf rats, including sex differences.

　Four-week-old male and female SDTf rats were fed the standard diets (CE-2) or QF (CLEA Japan Inc.). During the feeding period, body weights, food intake and blood glucose levels were measured. At 27 weeks of age in male and 38 weeks of age in female, animals were necropsied, and organ weights were measured, and blood and kidneys were sampled. Blood biochemistry, histopathological observation in kidneys and gene expression analysis were conducted using the collected materials.

　In male SDTf rats, histopathological findings were as follows; enlargement, adhesion, mesangial hyperplasia and fibrosis of glomerulus and formation of urinary cast, dilation, regeneration, Armanni-Ebstein lesion, and inflammatory cell infiltration in tubules. Each lesion tends to become worse by feeding QF. Similar histopathological changes were found in female SDTf rats, but female showed severer mesangial hyperplasia, macrophage infiltration, and fibrosis of glomerulus and milder tubular lesions compared to male.

　From these results, QF feeding exacerbates legal lesion in SDTf rats in both male and female and it might be as a new diabetic kidney disease (DKD) model for tubules in male and for glomerulus in females.