scholarly journals Dexamethasone Treatment Reverses Cognitive Impairment but Increases Brain Oxidative Stress in Rats Submitted to Pneumococcal Meningitis

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Tatiana Barichello ◽  
Ana Lucia B. Santos ◽  
Cintia Silvestre ◽  
Jaqueline S. Generoso ◽  
Andreza L. Cipriano ◽  
...  

Pneumococcal meningitis is associated with a significant mortality rate and neurologic sequelae. The animals received either 10 μL of saline or aS. pneumoniaesuspension and were randomized into different groups: sham: placebo with dexamethasone 0.7 mg/kg/1 day; placebo with dexamethasone 0.2 mg/kg/7 days; meningitis groups: dexamethasone 0.7 mg/kg/1 day and dexamethasone 0.2 mg/kg/7 days. Ten days after induction we evaluated memory and oxidative stress parameters in hippocampus and cortex. In the step-down inhibitory avoidance task, we observed memory impairment in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The lipid peroxidation was increased in hippocampus in the meningitis groups with dexamethasone and in cortex only in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The protein carbonyl was increased in hippocampus in the meningitis groups with dexamethasone and in cortex in the meningitis groups with and without dexamethasone. There was a decrease in the proteins integrity in hippocampus in all groups receiving treatment with dexamethasone and in cortex in all groups with dexamethasone (0.7 mg/kg/1 day). The mitochondrial superoxide was increased in the hippocampus and cortex in the meningitis group with dexamethasone 0.2 mg/kg/7 days. Our findings demonstrate that dexamethasone reverted cognitive impairment but increased brain oxidative stress in hippocampus and cortex in Wistar rats ten days after pneumococcal meningitis induction.

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e041500
Author(s):  
Zoe Menczel Schrire ◽  
Craig L Phillips ◽  
Shantel L Duffy ◽  
Nathaniel S Marshall ◽  
Loren Mowszowski ◽  
...  

IntroductionMelatonin has multiple proposed therapeutic benefits including antioxidant properties, synchronisation of the circadian system and lowering of blood pressure. In this protocol, we outline a randomised controlled trial to assess the feasibility, acceptability and tolerability of higher dose (25 mg) melatonin to target brain oxidative stress and sleep disturbance in older adults with mild cognitive impairment (MCI).Methods and analysisThe study design is a randomised double-blind, placebo-controlled, parallel group trial. Forty individuals with MCI will be recruited from the Healthy Brain Ageing Clinic, University of Sydney and from the community, and randomised to receive either 25 mg oral melatonin or placebo nightly for 12 weeks. The primary outcomes are feasibility of recruitment, acceptability of intervention and adherence to trial medication at 12 weeks. Secondary outcomes will include the effect of melatonin on brain oxidative stress as measured by magnetic resonance spectroscopy, blood pressure, blood biomarkers, mood, cognition and sleep. Outcomes will be collected at 6 and 12 weeks. The results of this feasibility trial will inform a future conclusive randomised controlled trial to specifically test the efficacy of melatonin on modifiable risk factors of dementia, as well as cognition and brain function. This will be the first trial to investigate the effect of melatonin in the population with MCI in this way, with the future aim of using this approach to reduce progression to dementia.Ethics and disseminationThis protocol has been approved by the Sydney Local Health District Ethics Committee (X18-0077). This randomised controlled trial will be conducted in compliance with the protocol published in the registry, the International Conference for Harmonisation on Good Clinical Practice and all other applicable regulatory requirements. The findings of the trial will be disseminated via conferences, publications and media, as applicable. Participants will be informed of results of the study at the conclusion of the trial. Eligible authors will include investigators who are involved in the conception and design of the study, the conduct of the trial, the analysis of the results, and reporting and presentation of study findings.Trial registration numberAustralian and New Zealand Clinical Trials Registry (ANZCTRN 12619000876190).Protocol versionV.8 15 October 2020.


2021 ◽  
Vol 19 (4) ◽  
pp. 470-476
Author(s):  
Chao Liu ◽  
Chao Liang ◽  
Jie Huang

We have investigated the effect of daphnetin on depressive-like behavior and oxidative stress caused by corticosterone in mice. To this end, we have analyzed the effect of corticosterone alone and combination of corticosterone and daphnetin on three behavioral indices of depressive-like behavior - sucrose consumption rate, forced swimming test, and tail suspension test as well as biochemical markers of oxidative stress - malondialdehyde, nitrite, protein carbonyl, nonprotein sulfhydryl and glutathione contents as well as hippocampal cell apoptosis. The results support the conclusion that daphnetin diminished corticosterone induced depressive like behavior and oxidative stress by activating Nrf2/HO-1 pathway.


2021 ◽  
Author(s):  
Chencen Lai ◽  
Qian Chen ◽  
Yuanting Ding ◽  
Songbai Su ◽  
Heng Liu ◽  
...  

Alzheimers disease is pathologically featured by abnormal accumulation of amyloid-beta plaque, neurofibrillary tangles, oxidative stress, neuroinflammation, and neurodegeneration. Metal dysregulation including excessive zinc released by presynaptic neurons plays an important role in tau pathology and oxidase activation. The activities of mammalian target of rapamycin (mTOR)/ ribosomal S6 protein kinase (p70S6K) are elevated in the brains of patients with Alzheimers disease. Zinc induces tau hyperphosphorylation via mTOR/P70S6K activation in vitro. However, the involvement of mTOR/P70S6K pathway in zinc-induced oxidative stress, tau degeneration, synaptic and cognitive impairment, has not been fully elucidated in vivo. Here we assessed in the effect of pathological concentration of zinc in SH-SY5Y cells by using biochemical assays and immunofluorescence staining. Rats (n = 18, male) were lateral ventricularly-injected with zinc and treated with rapamycin (intraperitoneal injection) for one week and assessed using Morris water maze. Evaluation of the oxidative stress, tau phorsphylation and synaptic impairment were performed using the hippocampus tissue of the rats by biochemical assays and immunofluorescence staining. Results from Morris water maze showed that the capacity of spatial memory is impaired in zinc-treated rats. Zinc sulfate significantly increased the levels of P-mTOR Ser2448, P-p70S6K Thr389, and P-tau Ser356, and decreased levels of Nrf2 and HO-1 in SH-SY5Y cells and in zinc-treated rats compared with control groups. Increased expressions of reactive oxygen species were observed in zinc sulfate-induced SH-SY5Y cells as well as in the hippocampus of zinc-injected rats. Rapamycin, an inhibitor of mTOR, rescued the zinc-induced increases in mTOR/p70S6K activations, tau phosphorylation and oxidative stress, as well as Nrf2/HO-1 inactivation, cognitive impairment and synaptic impairment reduced the expression of synapse-related proteins in zinc-injected rats. In conclusion, our findings imply that rapamycin prevents zinc-induced cognitive impairment and protects neurons from tau pathology, oxidative stress and synaptic impairment, by decreasing mTOR/p70S6K hyperactivity and increasing Nrf2/HO-1 activity.


2015 ◽  
Vol 54 (6) ◽  
pp. 1052-1064 ◽  
Author(s):  
Nergiz Hacer Turgut ◽  
Derya Guliz Mert ◽  
Haki Kara ◽  
Hatice Reyhan Egilmez ◽  
Emre Arslanbas ◽  
...  

2018 ◽  
Vol 34 (3) ◽  
pp. 418-430 ◽  
Author(s):  
Graciela Freitas Zarbato ◽  
Mariana Pereira de Souza Goldim ◽  
Amanda Della Giustina ◽  
Lucinéia Gainski Danielski ◽  
Khiany Mathias ◽  
...  

Life Sciences ◽  
2020 ◽  
Vol 253 ◽  
pp. 117703 ◽  
Author(s):  
Amin Mokhtari-Zaer ◽  
Mahmoud Hosseini ◽  
Hossein Salmani ◽  
Zohreh Arab ◽  
Parvin Zareian

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