Basic research

Translocator protein activates autophagy in diabetic neuropathic pain rats via regulation of the Keap1/Nrf2/HO-1 signaling

  • Nan GAO ,
  • Gem HAO ,
  • Bingjie MA ,
  • Tian JIN ,
  • Ke MA ,
  • Xiaoming LIU
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  • Department of Pain Management, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200082, China
LIU Xiaoming, E-mail: brightlxm@qq.com.

Received date: 2023-02-14

  Accepted date: 2023-05-25

  Online published: 2023-08-28

Supported by

National Natural Science Foundation of China(81771184)

Abstract

Objective ·To study the effects of translocator protein (TSPO) agonist Ro5-4864 on autophagy and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-derived-2-like 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling in diabetic neuropathic pain (DNP) rats. Methods ·Type 2 diabetic rats were established by high-fat diet and streptozotocin (STZ), and DNP rats were filtered by behavioral assessment. Twenty-four rats were randomly assigned to the Sham group, DNP group, TSPO agonist Ro5-4864 group (Ro group), and TSPO agonist Ro5-4864 combined with Nrf2 inhibitor ML385 group (Ro+ML385 group). Up-Down method was used to measure paw 50% mechanical withdrawal threshold (50% PMWT) of the rats before high-fat diet (baseline), and on Day 3, 7, 14, 21 and 28 after STZ. Sciatic nerves were collected on the last day to analyze the effects of Ro5-4864 on autophagy related proteins and Keap1/Nrf2/HO-1 signaling related proteins of DNP rats by using immunofluorescence and Western blotting. Results ·The 50% PMWT in the DNP group decreased from D3 to D28 (P=0.000 at all timing), and the expression of Bcl-2 interacting coiled-coil protein 1 (Beclin-1), microtubule-associated protein light chain 3-Ⅱ (LC3-Ⅱ), HO-1, and nuclear Nrf2 (P=0.000) were significantly reduced in the sciatic nerves of DNP rats (all P=0.000), compared with those in the sham group, but p62 was significantly increased (P=0.000). Administration of Ro5-4864 attenuated these changes in the rats of the Ro group. There was a gradual increase in the 50% PMWT, compared with that of the rats in the DNP group (D14 P=0.039, both D21 and D28 P=0.000), and the impairment of autophagy and the Keap1/Nrf2/HO-1 signaling was repaired, which was demonstrated by increases of Beclin-1, LC3-Ⅱ, HO-1, and nuclear Nrf2 protein contents (all P=0.000) and a decrease in p62 content (P=0.001). However, the beneficial effects of Ro5-4864 were totally abrogated by ML385 in rats of the Ro+ML385 group. Conclusion ·TSPO alleviates DNP in rats, of which the mechanism involves activation of autophagy via upregulation of the Keap1/Nrf2/HO-1 signaling in sciatic nerves. This study provides a new strategy for the treatment of DNP.

Cite this article

Nan GAO , Gem HAO , Bingjie MA , Tian JIN , Ke MA , Xiaoming LIU . Translocator protein activates autophagy in diabetic neuropathic pain rats via regulation of the Keap1/Nrf2/HO-1 signaling[J]. Journal of Shanghai Jiao Tong University (Medical Science), 2023 , 43(8) : 988 -996 . DOI: 10.3969/j.issn.1674-8115.2023.08.006

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