Effects of N-acetylcysteine and ebselen on arachidonic acid release from astrocytes and neurons cultured in normoxic or simulated ischemic conditions

In Vivo Intracerebral Administration of α-Ketoisocaproic Acid to Neonate Rats Disrupts Brain Redox Homeostasis and Promotes Neuronal Death, Glial Reactivity, and Myelination Injury

Maple syrup urine disease (MSUD) is caused by severe deficiency of branched-chain α-keto acid dehydrogenase complex activity, resulting in tissue accumulation of branched-chain α-keto acids and amino acids, particularly α-ketoisocaproic acid (KIC) and leucine. Affected patients regularly manifest with acute episodes of encephalopathy including seizures, coma, and potentially fatal brain edema during the newborn period. The present work investigated the ex vivo effects of a single intracerebroventricular injection of KIC to neonate rats on redox homeostasis and neurochemical markers of neuronal viability (neuronal nuclear protein (NeuN)), astrogliosis (glial fibrillary acidic protein (GFAP)), and myelination (myelin basic protein (MBP) and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase)) in the cerebral cortex and striatum. KIC significantly disturbed redox homeostasis in these brain structures 6 h after injection, as observed by increased 2',7'-dichlorofluorescein oxidation (reactive oxygen species generation), malondialdehyde levels (lipid oxidative damage), and carbonyl formation (protein oxidative damage), besides impairing the antioxidant defenses (diminished levels of reduced glutathione and altered glutathione peroxidase, glutathione reductase, and superoxide dismutase activities) in both cerebral structures. Noteworthy, the antioxidants N-acetylcysteine and melatonin attenuated or normalized most of the KIC-induced effects on redox homeostasis. Furthermore, a reduction of NeuN, MBP, and CNPase, and an increase of GFAP levels were observed at postnatal day 15, suggesting neuronal loss, myelination injury, and astrocyte reactivity, respectively. Our data indicate that disruption of redox homeostasis, associated with neural damage caused by acute intracerebral accumulation of KIC in the neonatal period may contribute to the neuropathology characteristic of MSUD patients.

N-Acetylcysteine Decreases Myocardial Content of Inflammatory Mediators Preventing the Development of Inflammation State and Oxidative Stress in Rats Subjected to a High-Fat Diet

Arachidonic acid (AA) is a key precursor for proinflammatory and anti-inflammatory derivatives that regulate the inflammatory response. The modulation of AA metabolism is a target for searching a therapeutic agent with potent anti-inflammatory action in cardiovascular disorders. Therefore, our study aims to determine the potential preventive impact of N-acetylcysteine (NAC) supplementation on myocardial inflammation and the occurrence of oxidative stress in obesity induced by high-fat feeding. The experiment was conducted for eight weeks on male Wistar rats fed a standard chow or a high-fat diet (HFD) with intragastric NAC supplementation. The Gas-Liquid Chromatography (GLC) method was used to quantify the plasma and myocardial AA levels in the selected lipid fraction. The expression of proteins included in the inflammation pathway was measured by the Western blot technique. The concentrations of arachidonic acid derivatives, cytokines and chemokines, and oxidative stress parameters were determined by the ELISA, colorimetric, and multiplex immunoassay kits. We established that in the left ventricle tissue NAC reduced AA concentration, especially in the phospholipid fraction. NAC administration ameliorated the COX-2 and 5-LOX expression, leading to a decrease in the PGE2 and LTC4 contents, respectively, and augmented the 12/15-LOX expression, increasing the LXA4 content. In obese rats, NAC ameliorated NF-κB expression, inhibiting the secretion of proinflammatory cytokines. NAC also affected the antioxidant levels in HFD rats through an increase in GSH and CAT contents with a simultaneous decrease in the levels of 4-HNE and MDA. We concluded that NAC treatment weakens the NF-κB signaling pathway, limiting the development of myocardial low-grade inflammation, and increasing the antioxidant content that may protect against the development of oxidative stress in rats with obesity induced by an HFD.

Attenuation of ecstasy-induced neurotoxicity by N-acetylcysteine

Exposure to 3, 4-methylenedioxymethamphetamine (MDMA) can lead to spatial memory impairments and hippocampal cell death. Numerous evidence indicates that the antioxidant N-acetylcysteine (NAC) exerts protective effects in the brain. The present study evaluates the effects of NAC on MDMA-induced neurotoxicity.

METHODS

We intraperitoneally injected 28 adult male Sprague-Dawley rats (200-250 g) with either 0, 10 mg/kg of MDMA, or 10 mg/kg of MDMA plus 100 mg/kg of NAC. Spatial memory was assessed with a Morris Water Maze (MWM). At the end of the study, rats' brains were removed to study the structure and ultrastructure of CA1, and measure Bcl-2 and Bax expressions in the hippocampus. In the MWM, NAC treatment significantly attenuated the MDMA-induced increase in distance traveled (p < 0.05) and escape latency (p < 0.001). The decreased time spent in the target quadrant in MDMA-treated animals was attenuated by NAC (p < 0.01). NAC significantly protected against MDMA-induced apoptosis and the up- and down-regulation of Bax and Bcl-2, respectively. These data have suggested that NAC could protect against behavioral changes and apoptosis in the hippocampus following administration of MDMA. NAC might be useful for the treatment of neurotoxicity in MDMA users.

The protective effect of ebselen on radiocontrast-induced nephrotoxicity

AIM

Radiocontrast-induced nephropathy has become one of the most important causes of renal acute failure. The most effective management of reducing the incidence of contrast nephropathy is to understand and prevent its causes. We aimed to investigate the protective role of ebselen against radiocontrast-induced nephrotoxicity in terms of tissue oxidant/antioxidant parameters and light microscopy in rats.

METHODS

Albino Wistar rats were randomly separated into four groups. The Group 1 rats were treated with sodium chloride as the control group, Group 2 with radiocontrast, Group 3 with radiocontrast plus ebselen, and Group 4 with ebselen alone. After 24 h, the animals over the experimental period were euthanized and blood samples were analyzed for blood urea nitrogen (BUN) and serum creatinine (Cr) levels. Kidney sections were analyzed for malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, as well as histopathological changes.

RESULTS

In the radiocontrast group, BUN, MDA, and GSH-Px levels increased while SOD activity decreased compared with the control group. These decays were improved by ebselen administration in the radiocontrast group. Significant histological deteriorations were observed in the radiocontrast group. We noted improvement in the histologic findings with ebselen administration.

CONCLUSION

These results indicate that ebselen might produce a protective mechanism against radiocontrast-induced nephrotoxicity.