Physical exercise is an effective therapy for neurorehabilitation. Exercise has been shown to induce remodeling and proliferation of astrocyte. Astrocytes potentially affect the recruitment and function of neurons; they could intensify responses of neurons and bring more neurons for the process of neuroplasticity. Interactions between astrocytes, microglia and neurons modulate neuroplasticity and, subsequently, neural circuit function. These cellular interactions promote the number and function of synapses, neurogenesis, and cerebrovascular remodeling. However, the roles and crosstalk of astrocytes with neurons and microglia and any subsequent neuroplastic effects have not been studied extensively in exercise-induced settings. This article discusses the impact of physical exercise on astrocyte proliferation and highlights the interplay between astrocytes, microglia and neurons. The crosstalk between these cells may enhance neuroplasticity, leading to the neuroplastic effects of exercise.
To provide an online service learning opportunity for medical students during the COVID-19 pandemic, medical faculty and librarians developed and implemented a “Debunking Medical Myths” module in which students learned to search for emerging medical literature, evaluate evidence, and use that evidence to create an infographics debunking a COVID-19-related myth for a non-medical audience. The resultant infographics are visually appealing and designed to make complex health information easy to understand. The module was well-received by students, who demonstrated a nuanced understanding of the use of infographics to convey health information, and students’ work was evaluated highly by community members.
Background. Cerebrovascular disease (CVD) is recognized as the leading cause of permanent disability worldwide. Depressive disorders are associated with increased incidence of CVD. The goal of this study was to establish a chronic restraint stress (CRS) model for mice and examine the effect of stress on cerebrovascular inflammation and oxidative stress responses. Methods. A total of forty 6-week-old male C57BL/6J mice were randomly divided into the CRS and control groups. In the CRS group ( n = 20 ), mice were placed in a well-ventilated Plexiglas tube for 6 hours per day for 28 consecutive days. On day 29, open field tests (OFT) and sucrose preference tests (SPT) were performed to assess depressive-like behaviors for the two groups ( n = 10 /group). Macrophage infiltration into the brain tissue upon stress was analyzed by measuring expression of macrophage marker (CD68) with immunofluorescence in both the CRS and control groups ( n = 10 /group). Cerebral microvasculature was isolated from the CRS and controls ( n = 10 /group). mRNA and protein expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), and macrophage chemoattractant protein-1 (MCP-1) in the brain vessels were measured by real-time PCR and Western blot ( n = 10 /group). Reactive oxygen species (ROS), hydrogen peroxide (H2O2), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activities were quantified by ELISA to study the oxidative profile of the brain vessels ( n = 10 /group). Additionally, mRNA and protein expressions of NOX subunits (gp91phox, p47phox, p67phox, and p22phox) in the cerebrovascular endothelium were analyzed by real-time PCR and Western blot ( n = 10 /group). Results. CRS decreased the total distances ( p < 0.05 ) and the time spent in the center zone in OFT ( p < 0.001 ) and sucrose preference test ratio in SPT ( p < 0.01 ). Positive ratio of CD68+ was increased with CRS in the entire region of the brain ( p < 0.001 ), reflecting increased macrophage infiltration. CRS increased the expression of inflammatory factors and oxidative stress in the cerebral microvasculature, including TNF-α ( p < 0.001 ), IL-1β ( p < 0.05 ), IL-6 ( p < 0.05 ), VCAM-1 ( p < 0.01 ), MCP-1 ( p < 0.01 ), ROS ( p < 0.001 ), and H2O2 ( p < 0.001 ). NADPH oxidase (NOX) was activated by CRS ( p < 0.01 ), and mRNA and protein expressions of NOX subunits (gp91phox, p47phox, p67phox, and p22phox) in brain microvasculature were found to be increased. Conclusions. To our knowledge, this is the first study to demonstrate that CRS induces depressive stress and causes inflammatory and oxidative stress responses in the brain microvasculature.
Objectives. Following cerebral ischemia, microRNA- (miR-) 29b in circulating blood is downregulated. This study investigates the underlying mechanism and implications of miR-29b in leukocyte induction. Methods. miR-29b from stroke patients and rats with middle cerebral artery occlusion (MCAO) were assessed using real-time polymerase chain reaction (PCR). miR-29b agomir was used to increase miR-29b expression in leukocytes via intravenous injection. C1q and tumor necrosis factor (C1QTNF) 6, interleukin- (IL-) 1β, zonula occludens- (ZO-) 1, occludin, and ischemic outcomes were assessed in MCAO rats. Additionally, hCMEC/D3 cells were subjected to oxygen–glucose deprivation (OGD) and cocultured with HL-60 cells. Results. miR-29b levels in neutrophils were found to be significantly lower in stroke patients compared with healthy controls, which may indicate its high diagnostic sensitivity and specificity for stroke. Moreover, miR-29b levels in leukocytes showed a negative correlation with National Institute of Health Stroke Scale (NIHSS) scores and C1QTNF6 levels. In MCAO rats, miR-29b overexpression reduced brain infarct volume and brain edema, decreasing IL-1β levels in leukocytes and in the brain 24 hours poststroke. miR-29b attenuated IL-1β expression via C1QTNF6 inhibition, leading to decreased blood-brain barrier (BBB) disruption and leukocyte infiltration. Moreover, miR-29b overexpression in HL-60 cells downregulated OGD-induced hCMEC/D3 cell apoptosis and increased ZO-1 and occludin levels in vitro. Conclusion. Leukocytic miR-29b attenuates inflammatory response by augmenting BBB integrity through C1QTNF6, suggesting a novel miR-29b-based therapeutic therapy for ischemic stroke.
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