RESUMO
Immune cells and interleukins play a crucial role in female-specific pain signaling. Interleukin 16 (IL-16) is a cytokine primarily associated with CD4+ T cell function. While previous studies have demonstrated the important role of spinal CD4+ T cells in neuropathic pain, the specific contribution of IL-16 to neuropathic pain remains unclear. In this study, by using a spinal nerve ligation (SNL)-induced neuropathic pain mice model, we found that SNL induced an increase in IL-16 mRNA levels, which persisted for a longer duration in female mice compared to male mice. Immunofluorescence analysis further confirmed enhanced IL-16- and CD4-positive signals in the spinal dorsal horn following SNL surgery in female mice. Knockdown of spinal IL-16 by siRNA or inhibition of CD4 by FGF22-IN-1, a CD4 inhibitor, attenuated established mechanical and thermal pain hypersensitivity induced by SNL. Furthermore, female mice injected with IL-16 intrathecally exhibited significant spontaneous pain, mechanical and thermal hyperalgesia, all of which could be alleviated by FGF22-IN-1 or a CD3 antibody. Additionally, IL-16 induced astrocyte activation but not microglial activation in the spinal dorsal horn of female mice. Meanwhile, astrocyte activation could be suppressed by the CD3 antibody. These results provide compelling evidence that IL-16 promotes astrocyte activation via CD4 on CD3+ T cells, which is critical for maintaining neuropathic pain in female mice.
RESUMO
STUDY OBJECTIVES: In this study, we conducted a cross-sectional analysis of the sleep characteristics in the elderly Chinese people to comprehensively investigate the association between sleep and cognitive function in the elderly people. We aimed to evaluate the most important demographic factors, conventional physiological indices and living habits that may influence sleep. METHODS: We surveyed 2901 elderly people (age ≥60 years old) face-to-face from 1 July to 31 December 2017, who were recruited from 17 communities of the Pudong New Area (Shanghai, China) by probability proportional to size. The Pittsburgh sleep quality index (PSQI) scale was used to describe the sleep features of each participant. Cognitive assessment was performed using the mini-mental state examination (MMSE) scale, Montreal cognitive assessment (MoCA) and the clinical dementia rating (CDR) scale. Those factors which potentially influence sleep and consequentially may impact cognition in the elderly people were evaluated, and the correlations of sleep characteristics and cognitive function were explored by the linear regression analysis. RESULTS: Altogether, there were 1287 (44.4%) people taking part in the investigation. Sleep quality was significantly correlated with MMSE and MoCA total scores. Healthy sleep (especially enough sleep) was correlated with better cognitive functions. Besides recognised relative factors (such as age, sex and living alone), the number of children was found to be a strong risk factor of poor sleep. Anxiety before sleep and light/noise interference significantly damaged sleep while an exercise routine was associated with better sleep. Moderate levels of reading, watching TV and household work were correlated with superior sleep quality. CONCLUSION: In conclusion, sleep characteristics correlate with cognitive decline in the elderly people, and they can be influenced by multiple demographic factors and living habits. To improve sleep quality, it may be important to change sleep environment, to be relax, to increase physical exercise and recreational activities moderately.