Characteristic glomerular lesions in the ExHC rat: a unique model for lipid-induced glomerular injury

ExHC rats were bred from the Sprague-Dawley strain and are highly susceptible to dietary hypercholesterolemic stimuli. Although chemical and histological examination of the aorta from ExHC rats fed a diet containing 3% cholesterol, 0.6% sodium cholate and 15% olive oil (high-cholesterol diet, HCD) has been reported, renal injury in this model has not been investigated to date. Therefore, we examined the renal pathological changes and proteinuria in this model. ExHC rats fed an HCD developed proteinuria and characteristic glomerular lesions within 4-8 weeks after initiation of the diet. The most striking glomerular change observed in this model was the marked accumulation of numerous lipid-filled foam cells, with a surface marker that identified them as macrophages, within the mesangial regions which could have been involved in focal and segmental glomerular sclerosis. Our study demonstrates that ExHC rats fed a cholesterol-supplemented diet develop glomerular injury that may be mediated by infiltrating macrophages. These results imply that ExHC rats may be well-suited for the use in investigations of the role of macrophages in the pathogenesis of lipid-induced glomerular injury.