Abstracto

Oxidative Stress Unify the Pathophysiological Mechanism of Experimental Hypertension and Diabetes of Spontaneously Hypertensive Stroke-Prone Rats

Stenio Fiorelli, Camille F França, Carlos Alberto Basílio de Oliveira, Marco Orsini, Rossano Fiorelli, Lucia Marques Vianna and Victor Hugo Bastos

This study has as an attempt to identify both: oxidative stress and a possible kidney injury among rats with severe hypertension and diabetes. Twenty-four, 20 wk age, kept in baseline for ten days, were subdivided in four groups of six animals each: SHRSP, SHRSPDb, WKY, WKYDb. Systolic pressure was measured by plethysmography. Blood glucose by Accu- Check glucometer (Roche), Blood Urea Nitrogen, serum creatinine, and 24hours urinary albumin followed the routine laboratory methodology. Blood homocysteine was determined by HPLC. The data was statistically analyzed by ANOVA and P<0.05 was considered significant. Afterwards, the rats under deep coma were sacrificed and the kidney removed for histophatological analysis. Those hypertensive rats presented the highest levels of blood urea nitrogen levels: SHRSP (40 ± 3 mg/dl) and SHRSPDb (57± 5 mg/dl) versus WKY (17 ± 2 mg/dl) and WKYDb (22 ± 3.5 mg/dl). At the same way, the serum creatinine levels were significantly increased in hypertensive rats: SHRSP (1.20 ± 0.02 mg/dl), SHRSP (1.27± 0.04 mg/dl) versus WKY (0.53 ± 0.02 mg/dl) and WKYDb (0.49 ± 0.01 mg/ dl). The 24 hours urinary albumin was also markedly increased in SHRSP strain: SHRSP (128 ± 1.2 mg/24 h) and SHRSPDb (125 ± 0.6 mg/24 h) versus WKY (15 ± 0.02 mg/24 h) and WKYDb (14.8 ± 0.01 mg/24 h).The Blood Homocysteine levels were significantly increased in the SHRSP strain: SHRSP (6.51 ± 0.40 μmol/l) and SHRSPDb (7.32 ± 0.61 μmol/l) as compared to those normotensive ones: WKY(3.80 ± 0.39 μmol/l) and WKYDb (5.20 ± 0.21 μmol/l). The histophatological assay confirmed a significant association between hypertension and renal damage, since the number of hyalinized glomeruli and vessel were higher in those hypertensive rats. However, the presence of an increased blood homocysteine levels in both strains suggests that an oxidative stress was common feature to the hypertension and diabetes.