Morphological features of the medial prefrontal cortex-nucleus reuniens pathway in the regulation of neuropathic pain

刘园坤 吕思婷 郭紫若 李依蔓 王淑敏 任淑婷 杨彦玲 史娟

doi:10.16098/j.issn.0529-1356.2026.02.004

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Acta Anatomica Sinica ›› 2026, Vol. 57 ›› Issue (2) : 169-176. DOI: 10.16098/j.issn.0529-1356.2026.02.004

Neurobiology

Morphological features of the medial prefrontal cortex-nucleus reuniens pathway in the regulation of neuropathic pain

LIU Yuan-kun^{1, 2}, LÜ Si-ting², GUO Zi-ruo¹, 2, LI Yi-man², WANG Shu-min², REN Shu-ting², YANG Yan-ling^1*, SHI Juan^2*

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Abstract

Objective To explore the morphological feature of the medial prefrontal cortex (mPFC) to nucleus reuniens (Re) projection pathway in mice with neuropathic pain. Methods Twelve C57BL/6 mice were divided into 3 groups according to the method employed. Retrograde tracer fluoro-gold (FG) was injected into the Re of mice subjected to spared nerve injury (SNI, n=3) or sham (n=3) operation. The distribution and pain responsivity of retrogradely-labeled neurons in the mPFC were observed with c-Fos immunofluorescent staining. Red retrobeads (Beads) were injected into the Re of normal mice (n=3), and the neurochemical feature of the mPFC-Re projection neurons was examined with calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) immunofluorescent staining. The c-Fos promoter-dependent anterograde virus was injected into the mPFC of SNI mice (n=3). The distribution of pain responsive mPFC-Re projection terminals and the target cell type were observed by calretinin (CR) immunofluorescent staining. Results The FG or Beads retrogradely-labeled neurons were mainly distributed in the deep layers (Ⅴ and Ⅵ) of cingulate cortex area 1 (Cg1), prelimbic (PrL), and infralimbic (IL) cortices of the mPFC. About 96.81% of labeled neurons showed CaMKⅡ immunoreactivities. SNI caused a significant decrease in the c-Fos expression and the number of FG/c-Fos double-labeled neurons, mostly strikingly in the PrL. The c-Fos-driven anterograde virus labeled terminals were mainly distributed in the ventrolateral region of the Re and formed close contacts with CR-positive neurons. Conclusion The projection neurons in the mPFC-Re pathway are dominantly excitatory neurons, and target on CR-positive neurons. Neuropathic pain results in the reduced activity of the mPFC-Re projection pathway.

Key words

Medial prefrontal cortex

/ Nucleus reunien / Neuropathic pain / Fluoro-gold / Recombinant adeno-associated virus / Immunofluorescence / Mouse

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LIU Yuan-kun, LÜ Si-ting, GUO Zi-ruo, LI Yi-man, WANG Shu-min, REN Shu-ting, YANG Yan-ling, SHI Juan. Morphological features of the medial prefrontal cortex-nucleus reuniens pathway in the regulation of neuropathic pain[J]. Acta Anatomica Sinica. 2026, 57(2): 169-176 https://doi.org/10.16098/j.issn.0529-1356.2026.02.004

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