Effect of diet composition on renal morphology in diabetic rats.

Streptozotocin-induced diabetic rats were fed rodent diets with standard (4.5%) or high (10%) polyunsaturated fatty acid content for up to 12 months. Diabetic rats fed a standard diet developed thickening of glomerular basement membrane (GBM) when compared to similarly fed controls (285 +/- 21 vs. 243 +/- 18 nm, respectively; p = 0.0003). No differences in GBM thickening were observed between control and diabetic rats fed high-fat diets (188 +/- 23 vs. 195 +/- 21 nm, respectively; p = n.s.). Regardless of diabetes, all rats fed high polyunsaturated fat diets had decreased GBM thickness compared to standard-fed rats (p = 0.0001). Glomerular and mesangial volumes were similar in control and diabetic rats fed standard or high fat diets. Diets high in polyunsaturated fatty acids prevent GBM thickening in diabetes and reduce GBM thickness in control rats.