[Chronic ethanol feeding induces oxidative stress in the rat retina: treatment with the antioxidant ebselen]

Topical Therapeutic Efficacy of Ebselen Against Multidrug-Resistant Staphylococcus aureus LT-1 Targeting Thioredoxin Reductase

As a thiol-dependent enzyme, thioredoxin reductase (TrxR) is a promising antibacterial drug target. Ebselen, an organo-selenium with well-characterized toxicology and pharmacology, was recently reported to have potent antibacterial activity against Staphylococcus aureus. In this paper, we demonstrated that ebselen has strong bactericidal activity against multidrug-resistant (MDR) S. aureus based on taking TrxR as a major target and disruption of the redox microenvironment. Further, the topical therapeutic efficacy of ebselen for staphylococcal skin infections was assessed in a rat model. Treatment with ebselen significantly reduced the bacterial load and the expression of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1 beta (IL-1β) in S. aureus skin lesions; further, wound healing and pathological changes were obvious improved in ebselen-treated rats compare to controls. Finally, ebselen was found to sensitize S. aureus to curcumin, which may be due to their synergistic effects in inhibiting bacterial TrxR. Altogether, ebselen is an effective topical antibacterial agent in animal model of MDR S. aureus LT-1 skin infection. This may lay the foundation for further analysis and development of ebselen as an antibacterial agent for topical treatment of MDR staphylococcal infections.

Synergistic therapeutic efficacy of ebselen and silver ions against multidrug-resistant Acinetobacter baumannii-induced urinary tract infections

Ebselen (EbSe), an organo-selenium compound with well-characterized toxicology and pharmacology, exhibited potent antibacterial activity against glutathione (GSH)-positive bacteria when combined with silver ions (Ag⁺).

Appraisal of the Antioxidative Potential of Aloe Barbadensis M. on Alcohol-Induced Oxidative Stress

This investigation estimated the anti-oxidative potential of Aloe barbadensis gel extracts in rats against alcohol-induced oxidative stress. Thirty male albino rats (5 each per group) were included in the experiments. Group A (positive control) and B (negative control) were administered 4 mg.kg–1 body weight distilled water and 50 % alcohol respectively for 21 days. Groups C and D were administered 50 % alcohol for the first 14 days followed by co-administration of 125 mg and 250 mg.kg−1 body weight extract with alcohol respectively for the last 7 days. Groups E and F were administered distilled water for the first 14 days followed by co-administration of 125 and 250 mg.kg−1 body weight Aloe barbadensis gel extracts with distilled water respectively for the last 7 days. The administration of alcohol resulted in a significant (P < 0.05) decrease in the specific activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and reduced glutathione (GSH) levels, while cholesterol (CHO), triglycerides (TAG), nitric oxide (NO) and malondialdehyde (MDA) concentrations were significantly increased when compared to the controls. Co-mobilization with Aloe barbadensis gel extracts for 7 days significantly reversed the deleterious effects of alcohol in the treated groups when compared to the alcohol group. This study indicated that Aloe barbadensis probably possesses anti-oxidative effects against alcohol–induced oxidative stress in rats.

The effects of thiamine pyrophosphate on ethanol induced optic nerve damage

Background

We aimed to determine the protective effects of thiamine pyrophosphate on ethanol induced optic neuropathy in an experimental model.

Methods

The rats were assigned into 4 groups, with 6 rats in each group as follows: healthy controls (HC group), only ethanol administered group (EtOH group), ethanol + thiamine pyrophosphate (20 mg/kg) administered group (TEt-20 group), and only thiamine pyrophosphate (20 mg/kg) (TPG group) administered group. To the rats in TEt-20 and TPG groups, 20 mg/kg thiamine pyrophosphate was administered via intraperitoneal route. To the rats in HC and EtOH groups, the same volume (0.5 ml) of distilled water as solvent was applied in the same manner. To the rats in TEt-20 and EtOH groups, one hour after application of thiamine pyrophosphate or distilled water, 32% ethanol with a dose of 5 g/kg was administered via oral gavage. This procedure was repeated once a day for 6 weeks. From the blood samples and tissues obtained from the rats, Malondialdehyde (MDA), reduced glutathione (GSH), interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) levels were studied. Histopathological evaluations were performed to the optic nerve tissue.

Results

Serum and tissue IL-1β, TNF-α and MDA levels were the highest in EtOH group which were significantly lower in thiamine pyrophosphate administered group (TEt-20 group) (p: 0.001). Serum and tissue reduced GSH levels were the lowest in EtOH group which were also significantly higher in TEt-20 group (p:0.001). In histopathological evaluations, in EtOH group there was obvious destruction and edema with hemorrhage and dilated blood vessels which were not present in any other groups.

Conclusions

There was an apparent destruction in ethanol administered group in histopathological analyses with an augmented level of oxidative stress markers and all those alterations were prevented with concomitant thiamine pyrophosphate administration. These protective effects of thiamine pyrophosphate are extremely important in chronic ethanol consumption. Clinical studies are warranted to define the exact role of thiamine pyrophosphate in prevention of ethanol induced optic neuropathy.

Reduction in central H2O2 levels prevents voluntary ethanol intake in mice: a role for the brain catalase-H2O2 system in alcohol binge drinking

BACKGROUND

Hydrogen peroxide (H2 O2 ) is the cosubstrate used by the enzyme catalase to form Compound I (the catalase-H2 O2 system), which is the major pathway for the conversion of ethanol (EtOH) into acetaldehyde in the brain. This centrally formed acetaldehyde has been shown to be involved in some of the psychopharmacological effects induced by EtOH in rodents, including voluntary alcohol intake. It has been observed that different levels of this enzyme in the central nervous system (CNS) result in variations in the amount of EtOH consumed. This has been interpreted to mean that the brain catalase-H2 O2 system, by determining EtOH metabolism, mediates alcohol self-administration. To date, however, the role of H2 O2 in voluntary EtOH drinking has not been investigated.

METHODS

In the present study, we explored the consequence of a reduction in cerebral H2 O2 levels in volitional EtOH ingestion. With this end in mind, we injected mice of the C57BL/6J strain intraperitoneally with the H2 O2 scavengers alpha-lipoic acid (LA; 0 to 50 mg/kg) or ebselen (Ebs; 0 to 25 mg/kg) 15 or 60 minutes, respectively, prior to offering them an EtOH (10%) solution following a drinking-in-the-dark procedure. The same procedure was followed to assess the selectivity of these compounds in altering EtOH intake by presenting mice with a (0.1%) solution of saccharin. In addition, we indirectly tested the ability of LA and Ebs to reduce brain H2 O2 availability.

RESULTS

The results showed that both LA and Ebs dose-dependently reduced voluntary EtOH intake, without altering saccharin consumption. Moreover, we demonstrated that these treatments decreased the central H2 O2 levels available to catalase.

CONCLUSIONS

Therefore, we propose that the amount of H2 O2 present in the CNS, by determining brain acetaldehyde formation by the catalase-H2 O2 system, could be a factor that determines an animal's propensity to consume EtOH.