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Aim To explore the effect of GSK-3β (glycogen synthase kinase-3 beta) inhibitor TDZD-8 on the neuropathic pain induced by side effects of chemotherapeutic drug oxaliplatin and the underlying mechanism. Methods The rat model of oxaliplatin-induced neuropathic pain was established by intraperitoneal injection of oxaliplatin for five consecutive days; the anti-nociception effect was detected by intrathecal injection of TDZD-8. The spontaneous flinches and mechanical pain threshold were used to detect the changes of pain behavior of rats; immunofluorescence and Western blot analysis were used to detect the changes of spinal inflammation and protein levels of rats. Results Intrathecally injection of TDZD-8 significantly alleviated oxaliplatin induced hyperalgesia in rats. TDZD-8 injection obviously inhibited the activation spinal microglia and the inflammatory reaction. TDZD-8 administration significantly inhibited GSK-3β activation. Conclusion TDZD-8 blocks GSK-3β activation, decreases NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome mediated spinal inflammation and alleviates neuropathic pain.
RESUMEN
OBJECTIVE@#To investigate the inhibitory effect of ANA-12 that blocks brain-derived neurotrophic factor (BDNF)/ tropomyosin receptor kinase B (TrkB) signaling on inflammatory pain in rats and explore the underlying mechanism.@*METHODS@#Forty-two adult SD rats were randomized into BDNF-induced acute pain group (n=24) and CFA-induced chronic pain group. The former group were randomly divided into 4 subgroups, including a control group, ANA-12 treatment group, BDNF treatment group, and BDNF+ANA-12 treatment group; the latter group were subgrouped into control group, CFA treatment group (CFA) and CFA + ANA-12 treatment group. The effects of ANA-12 treatment on pain behaviors of the rats with BDNF-induced acute pain and CFA-induced chronic inflammatory pain were observed. Western blotting was used to examine TrkB signaling and expressions of microglia marker protein Iba1 and TNF-α in the spinal cord of the rats.@*RESULTS@#BDNF injection into the subarachnoid space significantly increased the number of spontaneous paw withdrawal of the rats (P < 0.05), which was obviously reduced by ANA-12 treatment (P < 0.05). The rats with intraplantar injection of CFA, showed significantly increased ipsilateral mechanical stimulation sensitivity (P < 0.05), and ANA-12 treatment obviously increased the ipsilateral foot withdrawal threshold (P < 0.05). Treatment with either BDNF or CFA significantly increased the phosphorylation level of TrkB (Y705) in the spinal cord of the rats (P < 0.05), which was significantly lowered by ANA-12 treatment (P < 0.05). Treatment with BDNF and CFA both significantly up-regulated the expressions of Iba1 and TNF-α in the spinal cord (P < 0.05), but ANA-12 significantly reduced their expression levels (P < 0.05).@*CONCLUSION@#ANA-12 can reduce spinal cord inflammation and relieve acute and chronic pain in rats by targeted blocking of BDNF/TrkB signaling.