Modulation of Renal Function in a Metabolic Syndrome Rat Model by Antioxidants in Hibiscus sabdariffa L.

Abstract

Metabolic syndrome (MS) is the association of three or more pathologies among which obesity, hypertension, insulin resistance, dyslipidemia, and diabetes are included. It causes oxidative stress (OS) and renal dysfunction. Hibiscus sabdariffa L. (HSL) is a source of natural antioxidants that may control the renal damage caused by the MS. The objective of this work was to evaluate the effect of a 2% HSL infusion on renal function in a MS rat model induced by the administration of 30% sucrose in drinking water. 24 male Wistar rats were divided into 3 groups: Control rats, MS rats and MS + HSL rats. MS rats had increased body weight, systolic blood pressure, triglycerides, insulin, HOMA index, and leptin (p ≤ 0.04). Renal function was impaired by an increase in perfusion pressure in the isolated and perfused kidney, albuminuria (p ≤ 0.03), and by a decrease in clearance of creatinine (p ≤ 0.04). The activity of some antioxidant enzymes including the superoxide dismutase isoforms, peroxidases, glutathione peroxidase, glutathione-S-transferase was decreased (p ≤ 0.05). Lipoperoxidation and carbonylation were increased (p ≤ 0.001). The nitrates/nitrites ratio, total antioxidant capacity, glutathione levels and vitamin C were decreased (p ≤ 0.03). The treatment with 2% HSL reversed these alterations. The results suggest that the treatment with 2% HSL infusion protects renal function through its natural antioxidants which favor an improved renal vascular response. The infusion contributes to the increase in the glomerular filtration rate, by promoting an increase in the enzymatic and non-enzymatic antioxidant systems leading to a decrease in OS and reestablishing the normal renal function.

Oxidative Stress in Plasma from Patients with Marfan Syndrome Is Modulated by Deodorized Garlic Preliminary Findings

“…Glutathione peroxidase and glutathione-S-transferase activities were determinate spectrophotometrically in plasma of each patient as previously described [ 15 ]. 100 μ l of plasma was suspended in 1.6 ml of 50 mM phosphate buffer (pH 7.3), with added 0.2 mM reduced nicotinamide adenine nucleotide phosphate NADPH, 1 mM GSH, and 1 UI/ml glutathione reductase.…”

“…The NO 3 − was reduced to NO 2 − by the nitrate reductase enzyme reaction and detected by the technique of the Griess as previously described [ 15 ]. The NO 3 − was reduced to NO 2 − by the nitrate reductase enzyme reaction.…”

“…The absorbance was measured at 760 nm. The calibration curve was obtained using ascorbic acid standard solution [ 15 ].…”

“…Routine laboratory tests were For the activities of peroxidases, 35 μl of horseradish peroxidase was loaded to a final concentration of 178.5 μg as a standard, and 25 μl of plasma in the same conditions of the native gel was run as previously described. To observe the activity of the peroxidases, the gel was washed with distilled water three times, during 5 min, and it was then incubated with a mixture of 3 mg/ml 3,3,5,5-tetramethylbenzidine dissolved in a solution of ethanol: acetic acid: water (1 : 1 : 1) with H 2 O 2 for 10 min in the dark [15]. In these conditions, where peroxidases are present, the gel remains transparent and 3, 3, 5, 5-tetramethylbenzidine is oxidized showing a green coloration.…”

“…Then, the n-butanol phase was extracted, and the absorbance was measured. The calibration curve was obtained using tetraethoxypropane as standard [15]. 2.10.…”