Ameliorative Effects of α-Tocopherol and/or Coenzyme Q10 on Phenytoin-Induced Cognitive Impairment in Rats: Role of VEGF and BDNF-TrkB-CREB Pathway

Phenytoin is one of the most well-known antiepileptic drugs that cause cognitive impairment which is closely related to cAMP response element-binding protein (CREB) brain-derived neurotrophic factor (BDNF) signaling pathway. Moreover, vascular endothelial growth factor (VEGF), an endothelial growth factor, has a documented role in neurogenesis and neuronal survival and cognitive impairment. Therefore, this study aimed to investigate the influence of powerful antioxidants: α-Toc and CoQ10 alone or combined in the preservation of brain tissues and the maintenance of memory formation in phenytoin-induced cognitive impairment in rats. The following behavioral test novel object recognition and elevated plus maze were assessed after 14 days of treatment. Moreover, VEGF, BDNF, TrkB, and CREB gene expression levels in the hippocampus and prefrontal cortex were estimated using RT-PCR. Both α-Toc and CoQ10 alone or combined with phenytoin showed improvement in behavioral tests compared to phenytoin. Mechanistically, α-Toc and/or CoQ10 decreases the VEGF mRNA expression, while increases BDNF-TrKB-CREB mRNA levels in hippocampus and cortex of phenytoin-treated rats. Collectively, α-Toc and/or CoQ10 alleviated the phenytoin-induced cognitive impairment through suppressing oxidative damage. The underlying molecular mechanism of the treating compounds is related to the VEGF and enhancing BDNF-TrkB-CREB signaling pathway. Our study indicated the usefulness α-Toc or CoQ10 as an adjuvant to antiepileptic drugs with an advantage of preventing cognitive impairment and oxidative stress.

Molecular mechanisms of neuroprotective effect of adjuvant therapy with phenytoin in pentylenetetrazole-induced seizures: Impact on Sirt1/NRF2 signaling pathways

Current anticonvulsant therapies are principally aimed at suppressing neuronal hyperexcitability to prevent or control the incidence of seizures. However, the role of oxidative stress processes in seizures led to the proposition that antioxidant compounds may be considered as promising candidates for limiting the progression of epilepsy. Accordingly, the aim of this study is to determine if coenzyme Q10 (CoQ10) and alpha-tocopherol (α-Toc) have a neuroprotective effect in rats against the observed oxidative stress and inflammation during seizures induced by pentylenetetrazole (PTZ) in rats, and to study their interactions with the conventional antiseizure drug phenytoin (PHT), either alone or in combination. Overall, the data revealed that α-Toc and CoQ10 supplementation can ameliorate PTZ-induced seizures and recommended that nuclear factor erythroid 2-related factor 2 (NRF2) and silencing information regulator 1 (Sirt1) signaling pathways may exemplify strategic molecular targets for seizure therapies. The results of the present study provide novel mechanistic insights regarding the protective effects of antioxidants and suggest an efficient therapeutic strategy to attenuate seizures. Additionally, concurrent supplementation of CoQ10 and α-Toc may be more effective than either antioxidant alone in decreasing inflammation and oxidative stress in both cortical and hippocampal tissues. Also, CoQ10 and α-Toc effectively reverse the PHT-mediated alterations in the brain antioxidant status when compared to PHT only.

Association between oxidative stress and nutritional status in the elderly

Ageing is a dynamic and progressive process that is characterized by the occurrence of morphological, biochemical, functional and psychological changes in the organism. The aim of the present article is to provide updated concepts on oxidative stress, covering its importance in aging, as well as nutritional status and supplementation with antioxidants (substances that prevent or attenuate oxidation of oxidizable substrates, such as lipids, proteins, carbohydrates and deoxyribonucleic acid) in the geriatric population. Evidence suggests that there is an inverse relationship between oxidative stress and nutritional status in elderly individuals. Although an increase in oxidative stress in chronic diseases associated with aging has been proven, such as Parkinson's disease and Alzheimer's disease, up to now there has been no consistent clinical evidence proving the efficiency of supplementation with antioxidants against oxidative stress. In this context, supplementation is not recommended. On the other hand, the elderly should be encouraged to eat antioxidant foods, such as fruits and vegetables. Maintaining a normal weight (body mass index between 23 and 28 Kg/m(2)) should also be stimulated.

Oxidative stress on cardiotoxicity after treatment with single and multiple doses of doxorubicin

The mechanism of doxorubicin (DOX)-induced cardiotoxicity remains controversial. Wistar rats ( n = 66) received DOX injections intraperitoneally and were randomly assigned to 2 experimental protocols: (1) rats were killed before (−24 h, n = 8) and 24 h after (+24 h, n = 8) a single dose of DOX (4 mg/kg body weight) to determine the DOX acute effect and (2) rats ( n = 58) received 4 injections of DOX (4 mg/kg body weight/week) and were killed before the first injection (M0) and 1 week after each injection (M1, M2, M3, and M4) to determine the chronological effects. Animals used at M0 ( n = 8) were also used at moment −24 h of acute study. Cardiac total antioxidant performance (TAP), DNA damage, and morphology analyses were carried out at each time point. Single dose of DOX was associated with increased cardiac disarrangement, necrosis, and DNA damage (strand breaks (SBs) and oxidized pyrimidines) and decreased TAP. The chronological study showed an effect of a cumulative dose on body weight ( R = −0.99, p = 0.011), necrosis ( R = 1.00, p = 0.004), TAP ( R = 0.95, p = 0.049), and DNA SBs ( R = −0.95, p = 0.049). DNA SBs damage was negatively associated with TAP ( R = −0.98, p = 0.018), and necrosis ( R = −0.97, p = 0.027). Our results suggest that oxidative damage is associated with acute cardiotoxicity induced by a single dose of DOX only. Increased resistance to the oxidative stress is plausible for the multiple dose of DOX. Thus, different mechanisms may be involved in acute toxicity versus chronic toxicity.