Key points The maintenance of optimal mitochondrial content and function is critical for muscle health. Mitochondrial dynamics play key roles in mitochondrial quality control; however, the exact role that mitochondrial fission plays in skeletal muscle health remains unclear. Here we report knocking down Drp1 (a protein regulating mitochondrial fission) for 4 months in adult mouse skeletal muscle resulted in severe muscle atrophy (40–50%). Drp1 knockdown also led to a reduction in ADP‐stimulated respiration, an increase in markers of impaired autophagy and increased muscle regeneration, denervation, fibrosis and oxidative stress. Our data indicate that Drp1 is crucial for the maintenance of normal mitochondrial function and that Drp1 depletion severely impairs muscle health. Abstract Mitochondria play central roles in skeletal muscle physiology, including energy supply, regulation of energy‐sensitive signalling pathways, reactive oxygen species production/signalling, calcium homeostasis and the regulation of apoptosis. The maintenance of optimal mitochondrial content and function is therefore critical for muscle cells. Mitochondria are now well known as highly dynamic organelles, able to change their morphology through fusion and fission processes. Solid experimental evidence indicates that mitochondrial dynamics play key roles in mitochondrial quality control, and alteration in the expression of proteins regulating mitochondrial dynamics have been reported in many conditions associated with muscle atrophy and wasting. However, the exact role that mitochondrial fission plays in skeletal muscle health remains unclear. To address this issue, we investigated the impact of Drp1 (a protein regulating mitochondrial fission) knockdown, introduced via intramuscular injection of adeno‐associated virus (AAV) on adult mouse skeletal muscle. Knocking down Drp1 for 4 months resulted in very severe muscle atrophy (40–50%). Drp1 knockdown also led to a reduction in ADP‐stimulated respiration and increases in markers of muscle regeneration, denervation, fibrosis, oxidative stress and impaired autophagy. Our findings indicate that Drp1 is essential for the maintenance of normal mitochondrial function and that Drp1 suppression severely impairs muscle health.
Medium- or long-term intervention strategies for physical activity practice (PAP) need to be more effective in terms of their implementation by practitioners. The aim of this study was to evaluate the role of a teacher to implement the Team Pentathlon (TP) in order to improve the PAP in primary children. TP is a health education program made to improve PAP of children through individual and collective achievements. In this study, 203 children (age: 10–13 years) in grades 5 and 6 (intervention group (IG) N = 104, control group (CG) N = 99) were guided to increase their PAP during an eight-week period by five elementary school teachers (physical education or classroom) who had received four training sessions. Levels of PAP (self-reported) were compared between groups (IG/CG), sex, socioeconomic status of the schools and between teachers: baseline and during TP. Several teachers noted significant increases in PAP in the IG for both boys and girls (p ≤ 0.05 or p < 0.01), whereas others found only small improvements in PAP. One teacher even observed higher PAP in the CG. Training session records revealed that the teacher himself, how the TP is implemented, and proper resources were the three elements that explained the successful implementation of the TP program. The implementation of the TP significantly increased the PAP in primary children. Training sessions helped teachers to implement the TP program but personal engagement, motivation, respecting protocol, and an adequate environment are also necessary in improving the PAP of children.
Natural disasters have major consequences for mental health in low-and middle-income countries. Symptoms are often more pronounced among women. We analyzed patterns and predictors of distress among pregnant and non-pregnant women 3-4 and 15-16 months after a cyclone in Vanuatu, a low-to middle-income country. Distress levels were high among both pregnant and non-pregnant women, although pregnant women showed lower longer-term symptoms. Low dietary diversity predicted greater distress, which could affect women even in villages with little cyclone damage.
More research on sport for development and peace (SDP) organizations is needed to better understand their actual contributions to the United Nations (UN) Sustainable Development Goals (SDGs). Yet, the unstable, restricted, or even risky contexts in which many non-governmental organizations (NGOs) and SDP agencies sometimes operate often leave researchers to face important challenges to develop effective or feasible methods to work with such organizations. This study aimed to address the ontological and epistemological questions about what should be known about a given context in an organization before setting off on fieldwork. We propose a methodology, based on an actantial model (AM), as a method to analyze the nature and context of a project, to assess the actors involved in the project, and to establish if the global cost (i.e., material, temporal, financial, and physical) for conducting fieldwork is realistic and feasible of all the parties involved in the potential project. To illustrate this process, we analyzed the nature and context of an SDP project in Madagascar as the first step for potential collaborative research. As researchers, we do not want to invest time and energy to build up a fully developed field research project with an NGO in a context where it would not be realistic or feasible to conduct such research. Actually in this context, developing a research protocol without an implementation strategy might not only be detrimental to the researchers, but also to the NGO itself, where resources are often limited. Accordingly, the results from this preliminary field research demonstrate that an AM is a relevant analytical tool for obtaining insights about the context, the actors, and their relationships within an NGO. In conclusion, this model might be a useful instrument for conducting an initial analysis for the preliminary identification of the necessary conditions for the construction of a sustainable empirical research partnership with a given SDP project.
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