The role of endoplasmic reticulum stress in the pathogenesis of steroid-induced avascular necrosis of the femoral head / 中国组织工程研究

BACKGROUND: The pathogenesis of steroid-induced avascular necrosis of the femoral head is not clear, which may be related to endoplasmic reticulum stress. Controlling endoplasmic reticulum stress signal pathway may regulate autophagy and apoptosis, which has a certain preventive and therapeutic effect on the disease. OBJECTIVE: To explore the relationship between endoplasmic reticulum stress and hormone-induced autophagy and apoptosis, and to summarize the research progress of endoplasmic reticulum stress in the pathogenesis of steroid-induced avascular necrosis of the femoral head. METHODS: Relevant articles published from 2000 to 2020 were retrieved from PubMed, Web of Science, CNKI, WanFang, and VIP databases. The keywords were “endoplasmic reticulum stress, femur head necrosis, unfolded protein response, glucocorticoid, autophagy, apoptosis, ischaemia” in English and Chinese, respectively. The old and duplicate articles were excluded, and 81 articles were included for analysis and discussion. RESULTS AND CONCLUSION: Unfolded protein response can induce autophagy and apoptosis in cells to alleviate the three downstream signal pathways caused by endoplasmic reticulum stress. Endoplasmic reticulum stress is closely related to hormone-induced autophagy and apoptosis and femoral head ischemia. Endoplasmic reticulum stress may be a pathological link in the process of steroid-induced avascular necrosis of the femoral head. Hormone induces autophagy and apoptosis of cells by activating endoplasmic reticulum during ischemia and hypoxia and finally leads to osteonecrosis of the femoral head.

Relationship between the after-school schedule and bone mineral density in middle-school students in Shanghai / 中国学校卫生

Objective@#To investigate the relationship between after-school schedule and bone mineral density in middle-school students in Shanghai, to provide a reference for taking targeted measures.@*Methods@#From November 2017 to April 2018，eighteen classes of six middle schools in Shanghai (from urban districts, urban-suburb combined districts and suburban districts, respectively) were selected based on cluster random sampling. In each school, 2-4 classes were further randomly chosen in the 6th grade. Questionnaires were completed by 518 students and their parents, as well as physical examination and bone mineral density assessment.@*Results@#The average time spent on after-school academic learning during weekends was 4.0 (IQR: 2.0, 6.0) h. The Z-score of bone density was 0.3 (IQR: -0.7, 1.0). The smooth curve fit model showed a non-linear relationship between after-school academic learning time during weekends and the Z-scores of bone mineral densities. A two-stage multiple linear regression analysis was further applied according to the fit results, and the results showed that when total afterschool academic learning time <4.5 hours during weekends, the learning time was inversely correlated with the bone density Z-scores (β=-0.11,P=0.01), and when the learning time ≥4.5 hours, there was no significant correlation between the learning time and bone density Z-scores (β=0.02, P=0.65). Parent and student questionnaires showed that there was a non-linear relationship between students’ daily time spent on outdoor sports-related activities and bone density Z-scores. When time spent on the outdoor activities ≥45 minutes per day, outdoor activities were positively correlated with bone density Z-scores (P<0.05). However, when the time spent on outdoor activities <45 minutes per day, there was no significant relationship between outdoor activities and bone density Z-scores (P>0.05).@*Conclusion@#Too much time on after-school academic learning during weekends or limited time on outdoor activities are both related to impaired bone mineral densities. Therefore, a reasonable after-school schedule for middle-school students is important for physical development, especially during weekends.