Hyperlipidic diet induced glomerular morphometric alterations and renal damage in hypertensive rats

Abstract

The aim of this study was to evaluate the renal function in hypertensive hyperlipidic‐fed animals submitted to an acute NaCl overload. Weaned male spontaneously hypertensive rats (SHR) with 21 days old (40–50g) followed by 8 weeks, were divided into 4 groups (n=6/group): SHR Control (SC); SHR Salt (SS, NaCl 1% in drinking water for the 10 last days); SHR Hyperlipidic (SHL, hyperlipidic diet, 30% lipids) and SHR Hyperlipidic Salt (SHLS, hyperlipidic diet and NaCl). All the procedures followed the rules of the Committee of Research and Ethics of the Mackenzie University (CEUA Nº 127/08/2015). Metabolic evaluations consisted of glucose tolerance test, triglycerides, and total cholesterol measurements. Urine samples were collected during 24h using metabolic cages. At the end of the protocol, the animals were euthanized by anesthesia overload, serum was collected and the left kidney and the visceral fat pad were removed and weighted. Kidney slices were stained with picrosirius red to evaluate the area of the Bowman's capsule (AB) and space (BS), and glomerular tuft diameter (TD). Creatinine concentration (serum and urine) was determined by colorimetric methods and sodium concentration of the urine was measured using electrolyte analyzer. Hyperlipidic diet promoted glucose intolerance, increased triglycerides and visceral fat pad in SHL and SHLS groups. NaCl consumption determined an increase in urinary volume and sodium concentration in SS and SHLS groups. Hyperlipidic diet induced a reduction in TD (SHL: 82±0,6; SHLS: 83±0,5 vs. SC: 88±1,5 μm) and an increase of BS in SHL group (29,5%) and in SHLS group (43,4%), with no changes in AB, compared with SC. These results are associated with a reduction in glomerular filtration rate (creatinine clearance) (SHL: 0,7±0,1; SHLS: 0,8±0,2 vs. SC: 1,4±0,1 mL/min). In conclusion, our data suggests that hyperlipidic diet in hypertensive animals changed the renal morphometry with damage in renal function. However, when stimulated by NaCl consumption, there was no further impairment in renal function in hyperlipidic‐fed animals.Support or Funding InformationCAPES/Mackpesquisa