Melatonin and vitamin E alleviate homocysteine‐induced oxidative injury and apoptosis in endothelial cells

A relationship exists between hyperhomocysteinemia and cardiovascular diseases, although the underlying mechanisms are still incompletely defined. One possibility involves a homocysteine (Hcy)-induced increased oxidative stress. Melatonin (Mel) and vitamin E (vitE) are important anti-oxidants. The main purpose of this study was (1) to compare the effect of treatments with Mel, vitE or both, on Hcy-induced apoptosis in human umbilical vein endothelial cells (HUVECs), and (2) to investigate the underlying mechanisms. Cell proliferation assay was carried out by Water Soluble Tetrazolium-1 (WST-1) assay kit. Apoptotic index was calculated by TUNEL Assay. Anti-oxidant parameters were studied by measurement of reactive oxygen species (ROS) and lipid peroxidation (LPO) levels. mRNA and protein expression levels of apoptotic and anti-apoptotic genes and proteins were studied by quantitative real time polymerase chain reaction (qRT-PCR) and Western blotting experiments respectively. The results showed that treatments with Mel, vitE or Mel + vitE suppressed Hcy-induced cell death, with a higher efficiency for the Mel and Mel + vitE treatments. Our results suggests that the mechanisms by which these anti-oxidants protected endothelial cells include the decrease in ROS and LPO levels, an increase in cell migration, the downregulation of pro-apoptotic proteins Cas 3, Cas 9, Cyt C and Bax and the upregulation of anti-apoptotic protein Bcl 2. Collectively, these results revealed the protective role of vitE and Mel against Hcy-induced cell apoptosis, which may add insight into therapeutic approaches to Hcy-induced damages

Insulin increases homocysteine levels in a dose-dependent manner in diabetic rats

BACKGROUND:Even moderate increases in levels of homocysteine cause cardiovascular degeneration. Various genetic and nutritional factors affect plasma homocysteine concentrations, and hyperhomocysteinemia damages vascular endothelial cells; hence their functions are disrupted. In diabetes mellitus, homocysteine metabolism is altered and as a result, more severe diabetic complications are expected when hyperhomocysteinemia occurs.METHODS:In the present study we experimentally induced diabetes in rats and examined effects of low or high dose of insulin administration on homocysteine metabolism.RESULTS:We determined that homocysteine levels were reduced in STZ-induced diabetic rats. This reduction was normalized by insulin in a dose-dependent manner. On the other hand, increased levels of lipid parameters (cholesterol, triglycerides, HDL) were reduced by insulin.CONCLUSIONS:Hcy level in experimentally induced insulin-dependent diabetes mellitus is decreased and injection of insulin normalizes Hcy levels in a dose-dependent manner. We speculate that insulin increases activities of enzymes of transsulfuration and remethylation reactions and hence speeds up conversion of Hcy to methionine and cysteine.</p

Daily rhythm of glutathione peroxidase activity, lipid peroxidation and glutathione levels in tissues of pinealectomized rats

Melatonin is a component of the antioxidant defense system since it has radical scavenging and antioxidant activities. In the present study, we aimed to investigate the endogenous rhythm of antioxidant enzyme glutathione peroxidase (GSH-Px) activity, oxidized glutathione (GSSG) and lipid peroxidation levels in tissues of pinealectomized rats (PINX). Rats were sacrificed by decapitation at 4 h intervals. GSH-Px activity, GSSG and lipid peroxidation levels showed a daily rhythm both in controls and in PINX rats. GSH-Px and GSSG exhibited the peak levels after the peak time of melatonin which was determined previously by other groups. Lipid peroxidation levels increased progressively during the night and started to decline before the GSH-Px peak time. These findings suggest that endogenous melatonin is involved in the night time increase of GSH-Px activity and GSSG levels and modulates the daily rhythm pattern of GSH-Px. In conclusion, pinealectomy which eliminates the melatonin rhythm has a supressor effect on GSH-Px activity levels.</p

Melatonin protects the central nervous system of rats against toluene-containing thinner intoxication by reducing reactive gliosis

Neuroprotective effects of melatonin against free radical damage have been studied extensively. Thinner containing 60-70% toluene is a neurotoxic mixture which is widely used as an aromatic industrial solvent. This product has been shown to cause functional and structural changes in the central nervous system. Toluene generates reactive oxygen species (ROS) and the toxic effects relating to these reactants. In the present study we investigated glial reactivity in hippocampus, cortex and cerebellum and the expression of glial fibrillary acidic protein (GFAP) after exposure of rats to toluene vapor (3000 ppm) for 45 days. We also examined the protective effects of melatonin against gliosis. Western blots demonstrated a marked elevation in total GFAP, a specific marker for astrocytes, by thinner fume inhalation in the hippocampus (P&lt;0.001), cortex (P&lt;0.01) and cerebellum (P&lt;0.05) of rats. Melatonin administration prevented the increase of total GFAP induced by thinner fume inhalation. Thinner exposure caused a significant increase of lipid peroxidation products (malondialdehyde and 4-hydroxyalkenals) in all brain regions (P&lt;0.01 for each region), and this elevation was also was inhibited by melatonin. Furthermore, melatonin augmented glutathione levels in all brain regions (P&lt;0.05 for each region) investigated. In conclusion, melatonin treatment may provide neuroprotection against toluene neurotoxicity by increasing the survival of glial cells possibly by directly scavenging ROS and by indirectly augmenting their antioxidant capacity.</p

Antioxidant vitamin levels in term and preterm infants and their relation to maternal vitamin status

BACKGROUND:Lipid peroxidation plays a vital role in the pathogenesis of many neonatal complications. Preterm babies are especially predisposed to lung diseases and retinopathy, probably due to a deficiency in their antioxidant systems. Vitamins E, A, and C are part of the natural antioxidant defense systems. We aimed to determine the levels of vitamins E, A, and C in maternal and cord blood plasma of term and preterm infants and to investigate the relationships between these levels.METHODS:In the present study we determined vitamin E, A, and C levels in the umbilical cord blood of term (n = 30) and preterm (n = 22) infants and their mothers by HPLC. Blood samples were taken during delivery.RESULTS:Levels of lipid soluble antioxidant vitamin E and A in cord blood were lower than maternal values (p &lt;0.01, p &lt;0.05, respectively). Conversely, the level of water-soluble vitamin C was higher in cord blood than in maternal level (p &lt;0.05). Significantly higher levels of vitamins E, A, and C were found in term babies as compared with those born preterm (p &lt;0.05).CONCLUSIONS:There was a positive correlation between maternal and cord blood levels of vitamins E and A (r = 0.775, r = 0.725, respectively). In conclusion, preterm babies have fewer lipid-soluble antioxidant vitamins in their serum compared to term infants. Therefore, it is possible to postulate that preterm infants are more susceptible to oxidative stress</p

Effects of Lamotrigine and Topiramate on Brain Maturation and Cognitive Functions in Offspring of Pregnant Rats - Preliminary Study

TUZCU, MEHMET/0000-0002-1329-3143; Bal, Ramazan/0000-0003-3829-8669; Baydas, Giyasettin/0000-0002-9206-3177WOS: 000346149200003PubMed: 25491681Background. Antiepileptic drugs (AED) which are used to treat seizures in pregnant women, infants, and young children may cause cognitive impairment or other uncertain injury. However, the precise mechanisms responsible for the negative effects of new AEDs like lamotrigine (LTG) and topiramate (TPM) in the developing brain are still unclear. Objectives. To investigate the GFAP, NCAM and S100B levels in the whole brain of newborn rats on postnatal 1 day and in the hippocampus of adult rats to find out the effect of TPM and LTG on cognitive impairment and brain maturation. Material and Methods. Twenty eight pregnant rats were randomly divided into 7 groups with 4 animals in each group. The first group, receiving no drugs, was assigned as the control group. The study groups received intraperitoneal TPM or LTG injections in each trimester. Western blot analysis of the GFAP, NCAM and S100B was performed in the offspring. Behavioral tests were performed at postnatal day 75. Results. The rats in the TPM-I and TPM-III groups had a significant impairment in escape latency on the 5th day as compared to the control rats in a Morris water maze test. In addition, in the expression of astrocyte derived markers, GFAP was upregulated, whereas S100 beta and NCAM were downregulated in the whole brain on postnatal day 1, in offspring exposed to LTG and TPM in utero. Conclusions. The detrimental effects of TPM and LTG appear to be confined particularly to the early stages of brain development. And TPM seems to have a partial role in the cognitive impairmen

Electrophysiological Properties of Octopus Neurons of the Cat Cochlear Nucleus: an In Vitro Study

Electrophysiological studies from mice in vitro have suggested that octopus cells of the mammalian ventral cochlear nucleus (VCN) are anatomically and biophysically specialized for detecting the coincident firing of a population of auditory nerve fibers. Recordings from cats in vivo have shown that octopus cells fire rapidly and with exceptional temporal precision as they convey the timing of that coincidence to higher auditory centers. The current study addresses the question whether the biophysical properties of octopus cells that have until now been examined only in mice, are shared by octopus cells in cats. Whole-cell patch-clamp recordings confirm that octopus cells in brain slices from kittens share the anatomical and biophysical features of octopus cells in mice. As in mice, octopus cells in kittens have large cell bodies and thick dendrites that extend in one direction. Voltage changes produced by depolarizing and hyperpolarizing current injection were small and rapid. Input resistances and membrane time constants in octopus cells of 16-day-old kittens were 15.8 ± 1.5 MΩ (n = 16) and 1.28 ± 0.3 ms (n = 16), respectively. Octopus cells fired only a single action potential at the onset of a depolarizing current pulse; suprathreshold stimuli were greater than 1.8 nA. A tetrodotoxin (TTX)-sensitive sodium conductance (gNa) was responsible for the generation of the action potentials. Octopus cells displayed outward rectification that lasted for the duration of the depolarizing pulses. Hyperpolarizations produced by the injection of current exhibited a depolarizing sag of the membrane potential toward the resting value. A 4-aminopyridine (4-AP) and α-dendrotoxin (α-DTX)-sensitive, low-voltage-activated potassium conductance (gKL) and a ZD7288-sensitive, mixed-cation conductance (gh) were partially activated at rest, giving the octopus cells low input resistances and, as a consequence, brief time constants. In 7-day-old kittens, action potentials were taller and broader, input resistances higher, and both inward and outward rectification was weaker than in 16-day-old kittens. Also as in mice, stellate cells of the VCN fired trains of action potentials with constant interspike intervals when they were depolarized (n = 10) and bushy cells of the VCN fired only a single action potential at the onset of depolarizations (n = 6). In conclusion, the similarity of octopus cells in mice and kittens suggests that the anatomical and biophysical specializations that allow octopus cells to detect and convey synchronous firing among auditory nerve fibers are common to all mammals