Resveratrol improved kidney function and structure in malignantly hypertensive rats by restoration of antioxidant capacity and nitric oxide bioavailability

BACKGROUND

The main cause of death among patients with malignant hypertension is a kidney failure. The promising field in essential and malignant hypertension therapy could be centered on the amelioration of oxidative stress using antioxidant molecules like resveratrol. Resveratrol is a potent antioxidative agent naturally occurred in many plants that possess health-promoting properties.

METHODS

In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with anti-oxidative activity, in N^G-L-Arginine Methyl Ester (L-NAME) treated spontaneously hypertensive rats (SHR) - malignantly hypertensive rats (MHR).

RESULTS

Resveratrol significantly improves oxidative damages by modulation of antioxidant enzymes and suppression of prooxidant factors in the kidney tissue of MHR. Enhanced antioxidant defense in the kidney improves renal function and ameliorates the morphological changes in this target organ. Besides, protective properties of resveratrol are followed by the restoration of the nitrogen oxide (NO) pathway. 4) Conclusion: Antioxidant therapy with resveratrol could represent promising therapeutical approach in hypertension, especially malignant, against kidney damage.

Mucoadhesive buccal tablets with propranolol hydrochloride: Formulation development and in vivo performances in experimental essential hypertension

The objective of this study was to formulate extended-release mucoadhesive buccal tablets of propranolol hydrochloride in order to provide a prolonged absorption of propranolol hydrochloride from the buccal mucosa and to reduce presystemic metabolism and thus provide a better therapeutic effect. Besides, the aim was to perform comparative in vivo pharmacokinetic and hemodynamic studies of the developed extended-release (ER) propranolol hydrochloride 10 mg mucoadhesive buccal tablets and commercial immediate-release (IR) propranolol hydrochloride 10 mg tablets in spontaneously hypertensive rats. Formulation with 15% polyethylene oxide showed the highest degree of propranolol hydrochloride permeation, satisfactory mucoadhesiveness, and extended-release of propranolol hydrochloride, thus it was selected for further in vivo study. The pharmacokinetic study in rats showed the superiority of ER mucoadhesive buccal tablets over IR tablets in terms of propranolol hydrochloride absorption extent (AUC values: 70.32 ± 19.56 versus 31.69 ± 6.97 µg·h/mL), although lower maximum plasma propranolol hydrochloride concentration (C_max) was achieved. However, no statistically significant difference was observed in C_max between these treatments. The hemodynamic study showed that ER mucoadhesive buccal tablets provide a more pronounced decrease primarily in heart rate, but also in systolic and diastolic arterial pressure, as well as a longer heart rate reduction compared to IR tablets.

Combined Angiotensin II Type-1 Receptor Blockade and Superoxide Anion Scavenging Affect the Post-Ischemic Kidney in Hypertensive Rats

Ischemic acute kidney injury is characterized by renal vasoconstriction, filtration failure, tubular obstruction, tubular backleak and overproduction of angiotensin II and reactive oxygen species. Considering this complexity, the aim of our study was to investigate the effects of angiotensin II type-1 receptor blocker - Losartan and superoxide anion scavenger - Tempol, in a combined treatment on acute kidney injury in postischemic hypertensive rats.

The experiment was performed in anesthetized, adult male spontaneously hypertensive rats. The right kidney was removed and the left renal artery was occluded for 40 minutes. Experimental groups received combined treatment (Losartan + Tempol) or saline in the femoral vein 5 minutes before, during and 175 minutes after clamp removal.

Hemodynamics and biochemical parameters were measured and kidney specimens were collected 24h after reperfusion. Histological examination was performed by optical microscopy.

Combined treatment improves renal haemodynamics parameters which were exacerbated due to acute kidney injury. Acute kidney injury significantly decreased creatinine and urea clearance and increased lipid peroxidation in the plasma. Treatment with Losartan and Tempol induced a significant increase of creatinine and urea clearance. Lipid peroxidation in the plasma decreased and glutathione peroxidase enzyme activity in the erythrocytes increased after Losartan + Tempol treatment. This combined treatment reduced cortico-medullary necrosis and tubular dilatation in the kidney.

Our results indicate that synergism of Losartan and Tempol treatment could have beneficial effects on blood pressure and kidney function, during postischemic acute kidney injury development in experimental hypertension.

Vibroacustic microvibrations enhance kidney blood supply, glomerular filtration and glutathione peroxidase activity in spontaneously hypertensive rats

Limited numbers of studies include research of microvibration therapy in experimental models. We examined effects of chronic vibroacustic-microvibration treatment on haemodynamics and anti-oxidative defense in experimental hypertension. Study was performed on chronically treated hypertensive and normotensive Wistar rats. Mean arterial pressure (MAP), cardiac output (CO), renal blood flow (RBF), glomerular filtration and activity of anti-oxidative enzymes were determined after three weeks treatment. Vibroacustic treatment had no influence on MAP and CO, but RBF was increased in both groups of treated rats. Additionally, vibroacustic treatment enhanced diuresis and increased glomerular filtration in hypertensive rats. Glutathione peroxidase (GSH-Px) activity was elevated in both treated rat strains, but activity of superoxide dismutase was unchanged. We conclude that microvibration treatment doesn't ameliorate hypertension but improves renal blood supply (trough diminished renal vascular resistance), glomerular filtration, diuresis, and enhances glutathione dependent anti-oxidant defense with more important beneficials in hypertensive animals.

Fractionated irradiation and haematopoiesis. III. Effect of time interval between fractions

The effect of total single fractionated irradiation with short time interval on haematopoietic regeneration of the bone marrow and spleen was investigated. Also, the importance of first dose, when dose of 600 R was divided in two unequal fractions with time interval of 300s was studied. The investigation was performed on 25 day old rats. The dose of 600 R (X-rays) was divided on: 500 + 100, 400 + 200, 300 + 300, 200 + 400 or 100 + 500 R with time interval of 150, 300 or 600s. Ten days after irradiation the changes in blood, bone marrow and spleen were observed. After unequal fractionated dose with interval of 600s slight effect was found. The results after intervals of 600s and 300s were significant, when the total dose was divided in two equal doses. The first dose has no promoting role in haematopoietic regeneration when total dose was unequally fractionated.

Abscopal effects of local fractionated X-irradiation of face and jaw region

The abscopal effects of high doses of X-irradiation, 6000 R given in 12 fractions locally on rat face and jaw region, upon the haematopoietic and lymphatic tissues, were studied. Haematological and pathophysiological studies were performed. Peripheral blood samples were taken after the 7th, 17th and 27th day during the course of the irradiation. 24 hours after the last irradiation the smears of femur bone-marrow were done. In the smears, the cells of erythrocyte and leukocyte series, as well as their mitotic index were determined. 24 hours after the irradiation the pieces of lymph nodes and salivary glands were taken for histological analysis. A significant depression of peripheral leukocyte counts was found in all observation intervals as well as the change in mitotic index of granulocyte series in bone marrow. No significant histological changes on the lymph nodes and salivary gland section were found 24 hours after the last irradiation.

Fractionated irradiation and haematopoiesis. II. The effect of bone-marrow cell transplants in conditions of split dose of irradiation

Haemoregeneration after the irradiation with 600 R was studied using two different fractions given before and after the transplantation of bone-marrow cells. The dose of 600 R was divided in two uneven fractions: 500 + 100 R, 400 + 200 R and 300 + 300 R. During the free interval between the two doses (5 min) transplantation of bone-marrow cells was performed. Recolonization of bone-marrow and spleen was analysed on the 10th day after treatment. For analysis, samples of blood, bone-marrow and spleen were used. Maximal effect was found in the experimental group of animals irradiated with 500 R before and with 100 R after marrow-cell transplantation. Minimal haematopoietic response was in the group irradiated with 300 R before and after transplantation. This points at the importance of the primary dose for acceptance of the transplants and their activation.

Fractionated irradiation and haematopoiesis. I. The effect of a differently fractionated radiation dose of 600 R

The effect of the same dose of irradiation (600 R) divided into two different fractions (500 + 100 R; 400 + 200 R; 300 + 300 R) upon the haematopoietic system of young rats (25 days old) was investigated. Free interval between the first and the second dose was 5 minutes. Changes were observed in bone-marrow, spleen and blood in all the experimental groups of 10 days after the irradiation. Spontaneous regeneration of haematopoiesis after a single dose of 600 R is higher than after division of this dose into two fractions, excluding the group where the dose was divided into two equal fractions. The most intensive haematopoietic repopulation was found in the group of rats irradiated with 300 + 300 R, where the primary dose was the smallest. In fractional conditions, the first dose is of primary importance for the repopulating capacity of the haematopoietic system regardless of the short free interval.

The effect of X-irradiation on phytohemagglutinin (PHA)-stimulated rat lymphocytes

The effect of X-irradiation on PHA-stimulated rat lymphocytes has been investigated. The animals were exposed to doses of 100 to 800 R. Blood obtained by cardiac puncture was defibrinated and the lymphocytes sedimented by Dextraven. Lymphocytes were separated from supernatant and cultivated for three days in standard medium supplemented with rat serum and PHA. It was found that irradiation reduces the percentage of blast cells in function of the doses of irradiation. This reduction is accompained by an increased number of macrophage-like cells. The labelling index with tritiated thymidine in PHA-transformed lymphocytes was also reduced following irradiation.