Abstract
Oxidative stress is a key mechanism of cellular damage during and after severe hypoxia. Accordingly, up-regulation of expression and activity of endogenous antioxidants is an important mechanism of cellular adaptation to hypoxia. Do endogenous antioxidants take part in postconditioning-induced neuroprotective mechanisms similarly to their participation in preconditioning-induced ones? In the present work the effect of postconditioning by 3-trial mild hypobaric hypoxia (360 Torr, 2 h, once a day) after 1 session of severe acute hypobaric hypoxia (180 Torr, 3 h) on the expression of Cu, Zn-superoxide dismutase (Cu, Zn-SOD) was studied by immunocytochemical analysis in areas CA1, CA2, CA3, CA4 and DG of hippocampus and in frontoparietal neocortex (NC) of male Wistar rats. Two time points were examined: 3 h after the last session of postconditioning that was 3 days after severe hypoxia and 24 h after the last session of postconditioning that was 4 days after severe hypoxia. It has been shown that postconditioning significantly increases the total number of Cu, Zn-SOD-immunoreactive cells (Nt) at least in two areas of hippocampus studied (CA2 and DG) compared to non-postconditioned rats at 3 days but not at 4 days after severe hypoxia. In contrast, in NC of postconditioned rats, Nt tends to increase compared to non-postconditioned animals at 4 days but not at 3 days after severe hypoxia. The effect of postconditioning on the number of intensely expressing Cu, Zn-SOD neurons differs in various areas and at various time points. The modification of Cu, Zn-SOD expression in some areas of hippocampus and NC, induced by 3-trial hypoxic postconditioning, correlates with the prevention of massive delayed apoptotic neuronal death and amelioration of functional disorders caused by severe hypoxia. Thus, Cu, Zn-SOD and other endogenous antioxidants may play, apparently, an important role in the treatment of severe hypoxia/ischemia stroke by postconditioning in brain neurons.
Highlights
Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia
The results of the present study indicate that development of the neuronal hypoxic tolerance induced by the three-trial, in contrast to one-trial, mild hypoxic preconditioning is apparently largely associated with the activation of CREB, as well as brain-derived neurotrophic factor (BDNF) and Bcl-2 overexpression
No significant differences in serum level of Solubile form of RAGE (sRAGE) where found between rapidly progressing and slow progressing subgroup of multiple sclerosis (MS) patients.Our results suggest for the role of sRAGE in MS ethiopathogenesis, but we did not find any association of sRAGE in serum with the rate of MS disability progression
Summary
Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia. The aim of the study was to characterize the effects of streptozocin (STZ)-indced diabetes on learning and memory of 5XFAD and wild-type (WT) mice in Morris water maze (MWM) at ages 2 and 6 months and on brain amyloid load. Existing evidence suggests GABAergic system is involved in pathophysiology of Alzheimer’s disease (AD) via inhibitory interneuron deficits (Verret et al, 2012) and decrease in functional GABAA receptors (Limon et al, 2012). Our concept: low doses of muscimol may prevent learning/memory deficits in intracerebroventricular (icv) streptozocin (STZ)-induced AD nontransgenic rat model. The Sigma-1 receptor is a chaperone protein that modulates intracellular calcium signalling of the endoplasmatic reticulum and is involved in learning and memory processes.The aim of the present study was to compare in vitro Ca2+ concentration modulating activity and in vivo behavioural effects of enantiomers of methylphenylpiracetam, a novel positive allosteric modulator of Sigma-1 receptors
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