Pain Management Center, Shanghai Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 210092, China.
Pain Management Center, Nanjing Jinling Hospital, Nanjing, 210002, China.
Diabet Med. 2023 Jun;40(6):e15090. doi: 10.1111/dme.15090. Epub 2023 Apr 3.
In diabetes, autophagy and the nuclear factor erythroid-derived-2-like 2 (Nrf2)-dependent antioxidant system are impaired. Translocator protein (TSPO) agonist Ro5-4864 alleviates neuropathic pain, including diabetic peripheral neuropathy (DPN). However, the precise mechanisms remain unclear. Thus, we investigated the effects of Ro5-4864 on autophagy and the Nrf2-dependent antioxidant system in the sciatic nerves of DPN rats.
All rats were randomly assigned to Sham or DPN group. After type 2 diabetes modelling (established by high-fat diet and streptozotocin injection) followed by behavioural tests, established DPN rats were randomly assigned to the DPN group, the Ro (TSPO agonist Ro5-4864) group, the Ro + 3-MA (autophagy inhibitor) group and the Ro + ML385 (Nrf2 inhibitor) group. Behavioural assessments were performed at baseline, on days 3, 7, 14, 21 and 28. Sciatic nerves were collected on day 28 for immunofluorescence, morphological and western blot analyses.
Ro5-4864 alleviated allodynia and increased myelin sheath thickness and myelin protein expression after DPN. Beclin-1 (p < 0.01) and LC3-II/LC3-I ratio (p < 0.01) decreased and p62 (p < 0.01) accumulated in the DPN rats. Ro5-4864 administration increased the Beclin-1 and LC3-II/LC3-I ratio and decreased p62 accumulation. Furthermore, nuclear Nrf2 contents (p < 0.01) and cytoplasmic HO-1 (p < 0.01) and NQO1 (p < 0.01) expressions were significantly inhibited in the DPN rat, which was also improved by Ro5-4864. All the beneficial effects were abrogated by 3-MA or ML385.
TSPO exhibited a potent analgesic effect and improved Schwann cell function and regeneration against DPN by activating the Nrf2-dependent antioxidant system and promoting autophagy.
在糖尿病中，自噬和核因子红细胞衍生 2 样 2（Nrf2）依赖性抗氧化系统受损。转位蛋白（TSPO）激动剂 Ro5-4864 可缓解包括糖尿病周围神经病变（DPN）在内的神经性疼痛。然而，确切的机制尚不清楚。因此，我们研究了 Ro5-4864 对 DPN 大鼠坐骨神经中自噬和 Nrf2 依赖性抗氧化系统的影响。
所有大鼠随机分为假手术组或 DPN 组。在建立 2 型糖尿病模型（高脂肪饮食和链脲佐菌素注射）后，进行行为学测试，随后将 DPN 大鼠随机分为 DPN 组、Ro（TSPO 激动剂 Ro5-4864）组、Ro+3-MA（自噬抑制剂）组和 Ro+ML385（Nrf2 抑制剂）组。在基线、第 3、7、14、21 和 28 天进行行为学评估。在第 28 天收集坐骨神经进行免疫荧光、形态学和 Western blot 分析。
Ro5-4864 缓解了 DPN 后的感觉异常，并增加了髓鞘厚度和髓鞘蛋白表达。Beclin-1（p<0.01）和 LC3-II/LC3-I 比值（p<0.01）下降，p62（p<0.01）积累在 DPN 大鼠中。Ro5-4864 给药增加了 Beclin-1 和 LC3-II/LC3-I 比值，并减少了 p62 的积累。此外，核 Nrf2 含量（p<0.01）和细胞质 HO-1（p<0.01）和 NQO1（p<0.01）表达在 DPN 大鼠中受到显著抑制，这一抑制也可被 Ro5-4864 改善。3-MA 或 ML385 阻断了所有这些有益作用。
TSPO 通过激活 Nrf2 依赖性抗氧化系统和促进自噬，对 DPN 表现出强大的镇痛作用，并改善施万细胞功能和再生。
