背根神经节中TLR4信号抑制对奥沙利铂诱导的神经病理性疼痛的影响及其相关机理

Oxaliplatin (OXA) was widely used to treat colorectal cancer. However, it can induce neuropathic pain (NeP). TLR4 was involved in the regulation of neuropathic pain. However, the roles and mechanisms of TLR4 in OXA-induced neuropathic pain are still unknown. Our current results showed that OXA increased the TLR4 and MyD88 expression in DRG. TLR4 gene knockout and eritoran (a inhibitor of TLR4) attenuated the OXA-induced neuropathic pain. Eritoran suppressed the OXA-induced the expression of ATF3 (a marker of neuron injury). In addition, eritoran can attenuate the OXA-induced neuron growth inhibition in vitro. In this project, the TLR4 and MyD88 knockout mice are used to investigate the OXA-induced neuropathic pain. The intrathecal technique is also built to explore the roles of eritoran and ST2825 (a inhibitor of MyD88 ) in the OXA-induced neuropathic pain. In addition, using cell culture in vitro, the effects of TLR4 signaling inhibition on TRPV1 inward currents and intracellular Ca2+ level which are closely related to neuropathic pain are also performed. The results would provide the crucial clues for the clinical treat of OXA-induced neuropathic pain.

奥沙利铂（OXA）广泛用于临床治疗结直肠癌，但它会诱发神经病理性疼痛（NeP）。TLR4信号参与了疼痛调节，但它在OXA诱导的NeP中的作用和机理还不清楚。我们发现：OXA会促进小鼠DRG中TLR4和MyD88的表达；TLR4基因敲除和依立托伦（ERI，TLR4抑制剂）可减轻OXA诱导的NeP；ERI可抑制OXA诱导的DRG神经元中ATF3（神经元损伤标志）表达。此外，ERI可体外抑制OXA引起的神经元生长抑制。说明TLR4信号抑制可减轻OXA对神经元的损伤。本项目利用TLR4和MyD88基因敲除小鼠及鞘内注射抑制剂抑制TLR4/MyD88信号，研究TLR4/MyD88信号抑制在减轻OXA诱导的Nep中的作用和机理。利用体外细胞培养，研究TLR4信号抑制对与疼痛密切相关的TRPV1内向电流及胞内Ca2+水平的影响。进一步阐述其电生理机制。结果对OXA诱导的NeP临床治疗具有重要意义。

奥沙利铂是继顺铂和卡铂后的第三代铂类化合物，在临床上是治疗晚期结直肠癌的一线化疗药物。但是它存在严重的外周性神经不良反应，且疼痛程度随剂量增加而加重，严重者甚至被迫中断治疗。本项目的目的是研究奥沙利铂诱导的神经病理性疼痛的机制。研究结果显示：1. 奥沙利铂可以促进小鼠背根神经节中TLR4和MyD88蛋白表达；2. TLR4信号抑制可以减轻奥沙利铂诱导的神经病理性疼痛；3. 依立托伦（ TLR4抑制剂）可减轻奥沙利铂诱导的神经病理性疼痛，并降低奥沙利铂诱导的IL-1b, ATF3，MyD88，和p65表达；4. 胞内髓样分化因子88（MyD88）( TLR4下游信号因子) 可减轻奥沙利铂诱导的神经病理性疼痛，并降低奥沙利铂诱导的IL-1b, ATF3，MyD88，和p65表达；5. ST2825 （MyD88抑制剂）可减轻奥沙利铂诱导的神经病理性疼痛，并降低奥沙利铂诱导的IL-1b, ATF3，MyD88，和p65表达。研究结果显示，TLR4信号抑制可减轻奥沙利铂诱导的神经病理性疼痛。这对研发减少奥沙利铂化疗结肠癌诱发的神经病理性疼痛等副作用的药物及其机理有非常重要的理论和临床意义。