Protective effect of grape seed and skin extract on garlic-induced erythrocyte oxidative stress.

High garlic dose could exert adverse health properties and grape seed and skin extract (GSSE) exhibit a variety of beneficial effects, even at high dose. In the present study we evaluated the toxic effect of high garlic dose treatment on antioxidant status of the blood compartment and the protective effect of GSSE. Rats were intraperitoneally (i.p.) administered either with garlic extract (5 g/kg bw) or GSSE (500 mg/kg bw) or a combination of garlic and GSSE at the same doses daily during one month. Plasma parameters and erythrocytes antioxidant status were evaluated. Data confirmed that high garlic dose induced anemia and a pro-oxidative state into erythrocytes characterized by increased malondialdehyde (MDA), carbonyl protein and antioxidant enzyme activities as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Garlic also elevated intracellular hydrogen peroxide (H(2)O(2)) and free iron whereas GSSE treatment counteracted almost all garlic deleterious effects. In conclusion, high garlic dose induced a pro-oxidative state into erythrocytes via the Fenton reaction between H(2)O(2) and free iron, and GSSE exerted antioxidant properties.

Resveratrol protects against acute chemotherapy toxicity induced by doxorubucin in rat erythrocyte and plasma.

Doxorubicin (Dox), a widely used antitumor anthracycline antibiotic, plays an undisputed key role in the treatment of many neoplasic diseases. In this study, the protective role of resveratrol against Dox-induced erythrocytes and plasma toxicity has been evaluated in rats. Animals were treated with resveratrol (25 mg/kg b.w.) by intraperitoneal injection during 8 days. At the 4(th) day of treatment, rats were intraperitoneally injected with a single dose of Dox (20 mg/kg b.w.). At the end of the treatment, blood samples were collected following standard procedure and processed for oxidative stress parameters (malondialdehyde (MDA), carbonyl protein, free iron, calcium and H(2)O(2) levels), transaminases and antioxidant enzymes as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Data showed that Dox drastically increased erythrocytes and plasma MDA, free iron, H(2)O(2) and carbonyl proteins but decreased calcium levels and also decreased erythrocytes CAT, POD and SOD activity. Besides, Dox decreased plasma CAT and SOD but unexpectedly increased POD activity. Dox also increased plasma ALT and AST levels and decreased them into erythrocytes. Co-treatment with resveratrol counteracted almost all Dox's effects. In conclusion, Dox induced a pro-oxidative stress into erythrocytes and resveratrol exerted real antioxidant properties which can be attributed, at least in part, to free iron and calcium modulation.

The role of myoglobin in retarding oxygen depletion in anoxic heart.

The present study explores the role of myoglobin (Mb) in retarding the development of anoxia in the perfused working rat heart. We examine this phenomenon by analyzing the behavior and the kinetics of Mb oxygenation and cytochrome aa3 (cytaa3) redoxation. Absorbance changes, measured at wavelength pairs specific to Mb and cytaa3, show parallelism between the Mb oxygenation status and the redox states of cytaa3. Induction of anoxia leads to early and accelerated Mb deoxygenation whereas cytaa3 reduction marks a slight delay and its rate is twice slower than that of Mb. Then, when Mb is desatured above 50%, the cytaa3 reduction becomes accelerated. With the reoxygenated perfusion following the anoxia, the rate of Mb reoxygenation is twice faster than that of the cytaa3 reoxidation. When the oxygen-binding function of Mb, in situ in the heart, is abolished by treatment with sodium nitrite (NaNO2), the redox kinetics of cytaa3 show significant perturbations. Induction of anoxia leads to a precocious and accelerated reduction of cytaa3, compared to the same anoxic heart before the treatment. At reoxygenation, the reoxidation rate of cytaa3 decreases significantly, compared to that before the treatment. Similarly, in the nitrite treated heart, the phosphocreatine (PCr) level decreases to 60% of the control, whereas the inorganic phosphate (Pi) level increases to 300%. ATP concentration, however, remains constant. We conclude from these results that Mb may support mitochondrial respiration at the critical levels of the myocardial O2 supply.

Scanning spectrophotometry for the dynamic study of tissue respiration in intact organs.

For use with intact perfused organs a spectrophotometer system has been developed, both for dual-wavelength absorption measurements and for spectral scanning. A monochromator is used for illumination and scanning in the visible and near infrared. Optic fibres conduct light to the specimen under examination and from the specimen to a detecting photomultiplier. System control is exercised by a microcomputer, which also processes the collected data. The performance of the system on isolated perfused rat heart is demonstrated, in the spectral scanning mode and in the dual-wavelength mode, by studying simultaneously the kinetics of cytochrome aa3, and myoglobin oxidation-reduction.

Role of a non-ionic detergent upon maintenance and radioisotopic determination of enzymes catechol-O-methyltransferase and monoamine oxidase in brain and adrenal tissues.

1. The effect of different concentrations of Triton-X-100, used as homogenization media for enzymes catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO), was investigated. 2. Brain and adrenal COMT showed significant activation when treated with 0.2% Triton-X-100. 3. The activity of MAO in the brain and adrenal tissue was markedly inhibited by Triton-X-100 and the concentration required to provoke the inhibition was found to be much lower than that required to activate COMT. 4. When the tissues were kept in KCl-Triton-X-100 (0.9%-0.2%) for longer periods to study time related responses, brain COMT showed progressive increases in activity up to 4 hours of treatment and the increase persisted till 24 hours. Similar treatment of MAO enzyme preparation with Triton-X-100 induced strong inhibition of the enzyme activity (60% at 5 minutes and 55% at 24 hours). 5. The results suggest that the use of Triton-X-100 should be considered with extra care for determination of catecholamine regulating enzymes. It can activate one enzyme system whereas inhibit the other one. Therefore, different homogenization medias are required for the assay of enzymes of metabolism (MAO and COMT) and synthesis (tyrosine hydroxylase, phenylethano-l-amine-N-methyltransferase and dopamine beta hydroxylase).