Meherzia Mokni

Protective effect of the octadecaneuropeptide on hydrogen peroxide‐induced oxidative stress and cell death in cultured rat astrocytes

J. Neurochem. (2011) 118, 416–428.

Effect of garlic's mode of administration on erythrocytes and plasma parameters in Wistar rat

Garlic preparations are recognized as hypolipidemic, cardioprotective and antihypertensive agents. However, there are some discrepancies about the beneficial effects of garlic according to dosage and mode of administration. We aimed to determine the ability of high dosage garlic (5 g/kg bw ) to modulate erythrocytes and plasma parameters when administered orally (p.o.) or via intraperitoneal (i.p.) route. With regard to erythrocytes parameters, p.o. garlic treatment was found to have beneficial effects as it increased hemoglobin and hematocrit levels. Garlic i.p. treatment showed detrimental activity as it decreased these parameters. Our results reveal that garlic administered by p.o. does not involve any significant variation on mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC). Nevertheless, garlic i.p. increased MCV but reduced the MCH. The MCHC remained invariable even in intraperitoneal way. Concerning plasma parameters, our data show that garlic did not induce any variation on glycaemia and plasma electrolytes whatever its mode of administration. High garlic dosage was found to be relatively safe when administered orally. Keywords: Garlic, erythrocytes, hemoglobin, hematocrit, glycaemia, plasmatic electrolytes, administration mode

Prenatal exposure to cigarette smoke enhances oxidative stress in astrocytes of neonatal rat

Abstract Oxidative stress is involved in the pathogenesis of smoking-related disease. Protection of astrocytes from oxidative insult appears essential to maintain brain function. In this study, we have investigated the effect of gestational cigarette exposure on astrocyte survival. Pregnant female were randomly allocated to the control group or to the cigarette smoke group in which they were placed in an exposure chamber and inhale three cigarettes smoke twice a day for a period of 20 days. The control group was kept in the exposure chamber for the same duration, but without exposure to cigarette smoke. Newborn rats from both groups were weighed 24 h after birth and then cerebral hemispheres were collected for astrocyte culture. Incubation of astrocytes isolated from animals exposed to cigarette smoke with 300 μM H2O2 for 1 h induced a significant decrease of the proportion of surviving cells compared to cells isolated form control animals. We have observed that H2O2-treated astroglial cells derived from cigarette smoke exposure showed more reduced superoxide dismutase and catalase activities than H2O2-treated astroglial cells from control animals. In conclusion, this study indicates that astroglial cells derived from newborn rats exposed in utero to cigarette smoke are more vulnerable to oxidative assault than cultured astrocytes obtained from control animals. These results point out the existence of excitotoxic lesions in newborn exposed in utero to cigarette smoke and suggest that despite their high antioxidative activities, astrocytes cannot survive and protect neurons under massive oxidative stress.

Modulation of heart redox status by garlic based on route of administration in rat

We analyzed the ability of high dosage garlic administered per orally (p.o.) or via intraperitoneal (i.p.) route to act on heart antioxidant status in rats. In this organ, p.o. garlic is an antioxidant as it decreased H 2 O 2 and lactate dehydrogenase (LDH) levels and increased free iron level. However, it had no effect on malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD) but decreased peroxidase (POD) activity. Intraperitoneal garlic is pro-oxidant as revealed by high MDA, LDH and H 2 O 2 levels. It also induced an increase in free iron deposition and in CAT and SOD activities, but this way of treatment has no effect on POD activity. It can be concluded therefore that high garlic dosage is safer when orally administered. These effects are free iron mediated and organ specific. Key words : Garlic, heart, redox status, administration way, lipoperoxidation, free iron, hydrogen peroxide.

Response of antioxidant enzymes to cadmium-induced cytotoxicity in rat cerebellar granule neurons

Abstract Cadmium (Cd) accumulates in the brain and can damage neurons via complex processes involving oxidative stress induction. In this study we used a homogenous population of neurons which are cerebellar granule neurons (CGNs) to investigate damage induced by Cd and its effects on antioxidant enzyme activity. The exposure of CGNs to increasing concentrations of Cd (2.5 μM-100 μM) during 24 h, 48 h, or 72 h led to the induction of neuronal death in a dose- and exposure time-dependent manner. The necrotic and/or apoptotic pathway involved in the cell death trigged by Cd seems to depend on the concentration of Cd and the exposure time. In addition to its cell damage, Cd was shown to affect the activity of superoxide dismutase (SOD) and catalase (CAT) depending on the concentration of Cd and the exposure time. We also found that the exposure to Cd induces a bigger change in SOD activity than in CAT activity. Taken together, our findings explain, in part, the mechanism of Cd toxicity in a specific type of neuron which can provide information related to neurological pathologies ascribed to Cd toxicity.

Grape seed extract mitigates high dosage garlic- induced toxic effects on erythrocyte and plasma parameters

High dosage garlic exerts adverse health properties and grape seed extract (GSE) exhibit a variety of beneficial effects, even at high dosage. In the present study we evaluated the toxic effect of high dosage garlic treatment on blood parameters and the protective effect of GSE co-treatment. Rats were intraperitoneally injected with 5 g/kg body weight (bw) crude garlic extract during one month and cotreated or not (vehicle 10% ethanol) with GSE (500 mg/kg bw). Blood parameters were evaluated. Data confirmed that high dosage garlic induced anemia, increased MCV, reduced the MCHC, but has no effect on MCH. Garlic also has no effect on glycemia, calcemia, natremia and kaliemia. GSE cotreatment counteracted almost all garlic’s effects. High dosage garlic induced a toxic effect into erythrocytes parameters and GSE has real contradictory property.