ABSTRACT
Post-amputation pain causes great suffering to amputees, but still no effective drugs are available due to its elusive mechanisms. Our previous clinical studies found that surgical removal or radiofrequency treatment of the neuroma at the axotomized nerve stump effectively relieves the phantom pain afflicting patients after amputation. This indicated an essential role of the residual nerve stump in the formation of chronic post-amputation pain (CPAP). However, the molecular mechanism by which the residual nerve stump or neuroma is involved and regulates CPAP is still a mystery. In this study, we found that nociceptors expressed the mechanosensitive ion channel TMEM63A and macrophages infiltrated into the dorsal root ganglion (DRG) neurons worked synergistically to promote CPAP. Histology and qRT-PCR showed that TMEM63A was mainly expressed in mechanical pain-producing non-peptidergic nociceptors in the DRG, and the expression of TMEM63A increased significantly both in the neuroma from amputated patients and the DRG in a mouse model of tibial nerve transfer (TNT). Behavioral tests showed that the mechanical, heat, and cold sensitivity were not affected in the Tmem63a-/- mice in the naïve state, suggesting the basal pain was not affected. In the inflammatory and post-amputation state, the mechanical allodynia but not the heat hyperalgesia or cold allodynia was significantly decreased in Tmem63a-/- mice. Further study showed that there was severe neuronal injury and macrophage infiltration in the DRG, tibial nerve, residual stump, and the neuroma-like structure of the TNT mouse model, Consistent with this, expression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β all increased dramatically in the DRG. Interestingly, the deletion of Tmem63a significantly reduced the macrophage infiltration in the DRG but not in the tibial nerve stump. Furthermore, the ablation of macrophages significantly reduced both the expression of Tmem63a and the mechanical allodynia in the TNT mouse model, indicating an interaction between nociceptors and macrophages, and that these two factors gang up together to regulate the formation of CPAP. This provides a new insight into the mechanisms underlying CPAP and potential drug targets its treatment.
Subject(s)
Animals , Mice , Amputation, Surgical , Chronic Pain/pathology , Disease Models, Animal , Ganglia, Spinal/pathology , Hyperalgesia/etiology , Ion Channels/metabolism , Macrophages , Neuroma/pathologyABSTRACT
Objective:To implement an intervention with community-dwelling middle-aged and elderly people through a new science promotion approach, and to evaluate changes in the level of bone health awareness.Methods:From April 2017 to June 2017, 200 community-dwelling middle-aged and elderly people aged 50 years and over were randomly included.They were divided into the intervention group receiving a new science promotion intervention(n=100, with 50 males and 50 females)and the control group(n=100, with 50 males and 50 females). Baseline and follow-up assessments of bone health awareness were performed before and after the one-year intervention.A questionnaire survey on preferences for different types of science promotion articles in WeChat accounts was conducted.Differences in scores for intervention effects before and after intervention were compared between the two groups.Potential influencing factors for the scale score were examined by a multi-factor analysis.Results:After one year of intervention, scores for intervention effects were higher in the intervention group than in the control group( P<0.001). In the intervention group, scores were higher after intervention than before intervention( P<0.001). In the control group, scores after follow-up were slightly higher than those at baseline(29.4±11.4 vs.27.9±10.1, P<0.001). The increase in scores before and after intervention was greater in the intervention group than in the control group( P<0.001). Baseline score, group designation, history of drinking and diabetes impacted the scores in middle-aged and elderly women, while other factors did not.Most middle-aged and older people preferred texts illustrated with pictures, and older people were more receptive to videos. Conclusions:The new science promotion method is beneficial to bone health management, can improve bone health awareness in middle-aged and elderly people.