29 research outputs found

    The demyelination and altered motor performance following electrolytic lesion in the ventrolateral white matter of spinal cord in male rats: Benefit of post-injury administration of estradiol

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    Introduction: Spinal cord injuries are accompanied with significant demyelination of axons and subsequent locomotor dysfunction. To identify the extent of damage following electrolytic lesion of ventrolateral white matter, essential area for initiation of locomotor activity, we assessed demyelination as well as alteration in motor performance. Moreover, the protective effect of estradiol as a candidate treatment for preservation of myelin and locomotor activity after injury was examined due to its antiapoptotic and anti-inflammatory activities. Methods: A unilateral electrolytic lesion positioned in the right ventrolateral funiculus (VLF) was applied following laminectomy at T8-T9. In the estradiol-treated injury group, animals received a pharmacological single dose of estradiol valerate (4 mg/kg) at 30min post injury. Locomotor function was assessed using rotarod and open field tasks during 4 weeks after injury. Results: Obtained results showed significant demyelination at the site of injury and caudal areas following lesion as well as altered motor performance. Post-spinal cord injury administration of estradiol enhanced white matter maintenance at the site of lesion, restored the level of myelin basic protein (MBP), decreased TUNEL positive cells and improved functional recovery. Conclusion: Taken together, these results indicate that demyelination after lesion in VLF may be a contributing factor to limited motor performance, and suggest that pharmacological doses of estradiol may have an early protective effect through sparing of white matter. © 2016, Iranian Society of Physiology and Pharmacology. All rights reserved

    Role of Microglia and Astrocyte in Central Pain Syndrome Following Electrolytic Lesion at the Spinothalamic Tract in Rats

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    Central pain syndrome (CPS) is a debilitating state and one of the consequences of spinal cord injury in patients. Many pathophysiological aspects of CPS are not well documented. Spinal glia activation has been identified as a key factor in the sensory component of chronic pain. In this study, the role of glial subtypes in the process of CPS induced by unilateral electrolytic lesion of spinothalamic tract (STT) is investigated. Male rats received a laminectomy at T8–T9 and then unilateral electrolytic lesion centered on the STT. Thermal and mechanical thresholds as well as locomotor function were measured on days 0, 3, 7, 14, 21, and 28 post-injuries by tail flick, von Frey filament, and open field tests, respectively. To investigate the spinal glial activation following denervation in STT-lesioned groups, Iba1 and GFAP were detected by immunohistochemistry and Western blotting at the same time points. Data showed that STT lesion significantly decreased thermal pain at day 3 in comparison with sham groups. Significant bilateral allodynia appeared in hind paws at day 14 after spinal cord injury and continued to day 28 (P<0.05). Additionally, electrolytic spinal lesion attenuated locomotor function of injured animals after 7 days (P<0.05). In both histological assessments and Western blotting, Iba1 increased at days 3 and 7 while increased GFAP occurred from day 14 to 28 after lesion. It appears that microglial activation is important in the early stages of pain development and astrocytic activation occurs later. These events may lead to behavioral outcomes especially central neuropathic pain

    Estradiol attenuates spinal cord injury-induced pain by suppressing microglial activation in thalamic VPL nuclei of rats.

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    In our previous study we showed that central pain syndrome (CPS) induced by electrolytic injury caused in the unilateral spinothalamic tract (STT) is a concomitant of glial alteration at the site of injury. Here, we investigated the activity of glial cells in thalamic ventral posterolateral nuclei (VPL) and their contribution to CPS. We also examined whether post-injury administration of a pharmacological dose of estradiol can attenuate CPS and associated molecular changes. Based on the results,in the ipsilateral VPL the microglial phenotype switched o hyperactive mode and Iba1 expression was increased significantly on days 21 and 28 post-injury. The same feature was observed in contralateral VPL on day 28 (P<.05). These changes were strongly correlated with the onset of CPS (r(2)=0.670). STT injury did not induce significant astroglial response in both ipsilateral and contralateral VPL. Estradiol attenuated bilateral mechanical hypersensitivity 14 days after STT lesion (P<.05). Estradiol also suppressed microglial activation in the VPL. Taken together, these findings indicate that selective STT lesion induces bilateral microglia activation in VPL which might contribute to mechanical hypersensitivity. Furthermore, a pharmacological dose of estradiol reduces central pain possibly via suppression of glial activity in VPL region

    Acute Transplantation of Human Olfactory Mucosa-Derived Olfactory Ensheathing Cells Fails to Improve Locomotor Recovery in Rats

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    Olfactory ensheathing cells-based therapy for spinal cord injury (SCI) repair has been a possible treatment for clinical study because of their safety in autologous transplantation and potential regenerative capability. However, there are contradictory reports on the results after transplantation in animal models. The purpose of this research was to investigate the effect of acute transplantation of human mucosa-derived olfactory ensheathing cells (OECs) on the repair of the spinal cord. Human olfactory ensheathing cells were isolated from the human mucosa and cultured under supplemented neuronal cell culture medium. They were characterized by immunocytochemistry for olfactory ensheathing cell markers. We induced spinal cord injury at T8-T9 of rats by aneurysm clips and simultaneously injected two million OECs into subarachnoid space of spinal cord. Sensory and motor behaviors were recorded by tail-flick reflex (TFR) and BBB scores, respectively every week for seven weeks after injury. Morphology and S100-beta antigen expression in olfactory ensheathing cells of the human olfactory mucosa was confirmed by immunostaining. OECs transplantation did not recover inflammation, neuronal vacuolation, hemorrhage, and cyst formation. These findings suggest that OECs transplantation in this experimental setting did not lead to tissue regeneration to enhance locomotion. These results broaden current knowledge and are additions to the science and literature

    The psychological science accelerator’s COVID-19 rapid-response dataset

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    In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data

    The Psychological Science Accelerator's COVID-19 rapid-response dataset

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    In COVID-19 Health Messaging, Loss Framing Increases Anxiety with Little-to-No Concomitant Benefits: Experimental Evidence from 84 Countries

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    The COVID-19 pandemic (and its aftermath) highlights a critical need to communicate health information effectively to the global public. Given that subtle differences in information framing can have meaningful effects on behavior, behavioral science research highlights a pressing question: Is it more effective to frame COVID-19 health messages in terms of potential losses (e.g., "If you do not practice these steps, you can endanger yourself and others") or potential gains (e.g., "If you practice these steps, you can protect yourself and others")? Collecting data in 48 languages from 15,929 participants in 84 countries, we experimentally tested the effects of message framing on COVID-19-related judgments, intentions, and feelings. Loss- (vs. gain-) framed messages increased self-reported anxiety among participants cross-nationally with little-to-no impact on policy attitudes, behavioral intentions, or information seeking relevant to pandemic risks. These results were consistent across 84 countries, three variations of the message framing wording, and 560 data processing and analytic choices. Thus, results provide an empirical answer to a global communication question and highlight the emotional toll of loss-framed messages. Critically, this work demonstrates the importance of considering unintended affective consequences when evaluating nudge-style interventions

    A global experiment on motivating social distancing during the COVID-19 pandemic

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    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

    A global experiment on motivating social distancing during the COVID-19 pandemic

    Get PDF
    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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