Brain research
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Neurons are damaged following prolonged exposure to high concentrations of corticosterone, particularly during chronic inflammatory and immune diseases. One of the main mechanisms underlying neuronal injury is apoptosis. In the present study the neuroprotective effects of icariin, an active natural ingredient from the Chinese plant Epimedium sagittatum maxim against corticosterone-induced apoptosis were examined in primary cultured rat hippocampal neuronal cells. ⋯ Using western blot analysis, corticosterone activated p38MAPK, extracellular regulated kinase 1/2(ERK1/2) ,and c-jun N-terminal protein kinase 1(JNK1) ,while icariin blocked p38 MAPK, but not JNK1 or ERK1/2. Pharmacological approaches showed that the activation of p38MAPK plays a critical role in corticosterone-induced mitochondrial dysfunction and apoptosis. Taken together, the present results suggest that the protective effects of icariin on apoptosis in hippocampal neuronal cells are potentially mediated through blockade of p38 MAPK phosphorylation.
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Comparative Study
Resveratrol improves neuron protection and functional recovery in rat model of spinal cord injury.
Researches on the pathology of spinal cord injury (SCI) have been recently focused on oxidative radicals stress and inflammation associated neuronal apoptosis. Resveratrol, a natural phenolic compound, has been extensively studied and shown a wide variety of health beneficial effects, including prevention of cardiovascular diseases and cancer and neuroprotective activities. However, the study of its potential role in neuroprotection and underlying mechanism in SCI model has been limited. ⋯ In addition, resveratrol treatment suppressed immunoreactivity and expression of inflammatory cytokines including IL-1β, IL-10, TNF-α, and myeloperoxidase (MPO) after SCI, suggesting an anti-inflammation effect of resveratrol. Finally, resveratrol treatment inhibited injury-induced apoptosis as assessed by electrical microscopy and TUNEL staining and affected the expression level of apoptosis-related gene Bax, Bcl-2 and caspase-3, which indicated its anti-apoptosis role after SCI. Our data suggest that resveratrol significantly promotes the recovery of rat dorsal neuronal function after SCI, and this effect is related to its characteristics of anti-oxidation, anti-inflammation and anti-apoptosis.
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In Parkinson's disease (PD), there is a significant loss of noradrenergic neurons in the locus coeruleus (LC) in addition to the loss of dopaminergic neurons in the substantia nigra (SN). The goal of this study was to determine if the surviving LC noradrenergic neurons in PD demonstrate compensatory changes in response to the neuronal loss, as observed in Alzheimer's disease (AD). Tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) mRNA expression in postmortem LC tissue of control and age-matched PD subjects demonstrated a significant reduction in the number of noradrenergic neurons in the LC of PD subjects. ⋯ In PD subjects, the loss of dendrites from surviving noradrenergic neurons was also apparent with TH-immunoreactivity (IR). This loss of LC dendritic innervation in PD subjects as measured by TH-IR was not due to LC neuronal loss because TH-IR in AD subjects was robust, despite a similar loss of LC neurons. These data suggest that there is a differential response of the noradrenergic nervous system in PD compared to AD in response to the loss of LC neurons.