Radiotherapy is one of the major clinical approaches for treatment of bone cancer pain. Activation of cAMP-PKA signaling pathway plays important roles in bone cancer pain. Here, we examined the effects of radiotherapy on bone cancer pain and accompanying abnormal activation of cAMP-PKA signaling. Female Sprague-Dawley rats were used and received tumor cell implantation (TCI) in rat tibia (TCI cancer pain model). Some of the rats that previously received TCI treatment were treated with X-ray radiation (radiotherapy). Thermal hyperalgesia and mechanical allodynia were measured and used for evaluating level of pain caused by TCI treatment. PKA mRNA expression in dorsal root ganglion (DRG) was detected by RT-PCR. Concentrations of cAMP, IL-1β, and TNF-α as well as PKA activity in DRG and the spinal cord were measured by ELISA. The results showed that radiotherapy significantly suppressed TCI-induced thermal hyperalgesia and mechanical allodynia. The level of PKA mRNA in DRG, cAMP concentration and PKA activity in DRG and in the spinal cord, and concentrations of IL-1β and TNF-α in the spinal cord were significantly reduced by radiotherapy. In addition, radiotherapy also reduced TCI-induced bone loss. These findings suggest that radiotherapy may suppress bone cancer pain through inhibition of activation of cAMP-PKA signaling pathway in DRG and the spinal cord.

Background and Purpose Neurotoxicity of anesthetics has been widely observed by clinicians. It is reported that inflammation and oxidative stress are involved in the pathological process. In the present study, we aimed to assess the therapeutic effects of agomelatine against isoflurane-induced inflammation and damage to brain endothelial cells. Materials and Methods MTT assay was used to detect cell viability in order to determine the optimized concentration of agomelatine. The bEnd.3 brain endothelial cells were treated with 2% isoflurane in the presence or absence of agomelatine (5, 10 μM) for 24 h. LDH release was evaluated and the ROS levels were checked using DHE staining assay. The expressions of IL-6, IL-8, TNF-α, VEGF, TF, VCAM-1, and ICAM-1 were evaluated using real-time PCR and ELISA. Real-time PCR and Western blot analysis were used to determine the expression level of Egr-1. Results The decreased cell viability promoted LDH release and elevated ROS levels induced by isoflurane were significantly reversed by the introduction of agomelatine in a dose-dependent manner. The expression levels of IL-6, IL-8, TNF-α, VEGF, TF, VCAM-1, and ICAM-1 were elevated by stimulation with isoflurane, which were significantly suppressed by the administration of agomelatine. The up-regulation of transcriptional factor Egr-1 induced by isoflurane was down-regulated by agomelatine. Conclusion Agomelatine might attenuate isoflurane-induced inflammation and damage via down-regulating Egr-1 in brain endothelial cells.

Chronic constriction injury (CCI) of the sciatic nerve was used to establish neuropathic pain (NP) models in rats. CCI rats were then treated with propofol (Pro) and their paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured. In addition, the expression patterns of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), and IL‐10 were detected. CCI rats treated with propofol were further injected with antagomiR‐140‐3p to verify the role of miR‐140‐3p in propofol's analgesic actions. In addition to confirming the relationship between miR‐140‐3p and JAG1, the expression patterns of JAG1 itself were detected. Propofol‐treated CCI rats were also injected with Ad‐JAG1 (adenovirus‐packaged JAG1 overexpression vector and Ad‐NC) to test the role of JAG1 in propofol's analgesic mechanism of action. Finally, the levels of JAG1 and Notch pathway‐related proteins were detected Results Propofol was found to alleviate NP, including thermal hyperalgesia and mechanical pain threshold. Propofol could also ameliorate neuroinflammation by up‐regulating the expression of IL‐10 and inhibiting the release of TNF‐α and IL‐1β. Mechanically, propofol enhanced the amount of miR‐140‐3p in CCI rats via the regulation of JAG1. Down‐regulation of miR‐140‐3p, or up‐regulation of JAG1, could reduce the protective effect of propofol against NP. Propofol inhibited the activation of Notch signaling via miR‐140‐3p/JAG1 to realize its analgesic effect Conclusion Our findings indicated that propofol inhibits inflammatory responses and the Notch signaling pathway via miR‐140‐3p/JAG1 to alleviate NP. These data provide evidence to support a potential clinical therapy for NP.

As a renowned anesthetic, propofol exerts excellent analgesic function in nerve injury. However, the underlying mechanism of propofol on neuropathic pain (NP) remains unknown. The research aims to analyze propofol’s analgesia mechanism to alleviate NP in CCI rats. The chronic constriction injury (CCI) of sciatic nerve was used to established NP rat models. CCI rats were treated with propofol and its paw withdrawal mechanical threshold (PMWT) and paw withdraw thermal latency (PWTL) were measured. The expressions of TNF-α, IL-1β and IL-10 were detected. CCI rats with propofol treatment were injected with antagomiR-140-3p. After the targeting relationship between miR-140-3p and JAG1 was checked, JAG1 expression was detected. Propofol-treated CCI rats were further injected with Ad-JAG1. Finally, the levels of JAG1 and Notch pathway-related proteins were detected. As a result, propofol could alleviate NP, including thermal hyperalgesia and mechanical pain threshold, and ameliorate neuroinflammation. Mechanically, propofol enhanced the level of miR-140-3p in CCI rats. JAG1 was a direct target of miR-140-3p. The downregulation of miR-140-3p or upregulation of JAG1 could reduce the protective effect of propofol against NP. Propofol inhibited activation of Notch signaling via miR-140-3p/JAG1. Overall, Propofol could inhibit the neuroinflammation and Notch signaling pathway via miR-140-3p/JAG1 to alleviate NP.