慢性神經壓迫損傷誘發小鼠神經性疼痛的中幅與微幅之活體影像評估方式

Meso- and Micro- Intravital Imaging Assessments for Chronic Constriction Injury-Induced Neuropathic Pain in Mice

紀瀚雄(Han-Hsiung Chi)

指導教授 ： 嚴震東

國立臺灣大學/生命科學院/生命科學系/博士(2021年)

https://doi.org/10.6342/NTU202100764

摘要

已知許多周邊神經在神經壓迫性損傷之後會有退化的現象，然而神經損傷所造成的變化與疼痛的嚴重程度，兩者之間的相關性仍是未知的。在本研究中，我們發明了透過雙光子螢光顯微鏡的中幅與微幅的活體影像評估方式，來長期觀察慢性壓迫性損傷(chronic constriction injury, CCI)後，電壓門控鈉離子通道1.8基因轉殖螢光小鼠(Nav1.8-Cre-tdTomato mice)後腳掌皮下的神經纖維變化。我們比較三種不同的分析方式來對應全腳掌神經評分與局部活體包含了神經叢長度與神經末梢變化的評分，來尋找一個與機械力過敏感現象最相關的新型生物性標誌物。結果顯示CCI造成不同程度的皮下神經叢和表皮神經纖維受損。我們也發現Nav1.8神經纖維損失的時間點和機械力過敏感化發展相關。此外，使用非線性回歸模型分析全腳掌神經評分和局部活體神經分數，或使用多元線性回歸模型結合第五趾趾尖的局部活體內神經叢長度和末端數目變化，兩者均與機械性縮足閾值顯著相關並具有機械力過敏感化的預測效果。這些結果顯示出誘發的神經性神經痛既需要存活的神經且需要受損的神經。此外，這兩種評估方法均具有預測作用，可用作神經性疼痛的診斷和預後生物標誌物。

關鍵字

慢性壓迫性損傷 ； 皮下神經纖維 ； 活體雙光子螢光顯微鏡 ； 電壓門控鈉離子通道1.8 亞型 ； 神經性神經痛

並列摘要

Multiple peripheral nerves are known to degenerate after nerve compression injury, but the correlation between the extent of nerve alteration and pain severity remains unclear. Here, we developed meso- and micro- intravital imaging assessments via the two-photon fluorescence microscopy to longitudinally observe changes in cutaneous fibers in the hind paw of Nav1.8-tdTomato mice after chronic constriction injury (CCI). We compared three different analysis approaches for the whole-paw nerve score and the local intravital scores, including plexus length and terminal number changes, to search for a novel biomarker best correlated with the mechanical hypersensitivity. Results showed that CCI led to variable loss of the skin nerve plexus and intraepidermal nerve fibers. The timing of Nav1.8 nerve fiber loss correlated with the development of mechanical hypersensitivity. Moreover, using the non-linear regression model analyzed the whole-paw nerve score and the local intravital nerve scores, or using the multiple linear regression model combined the local intravital plexus length and terminal number changes in the fifth toe tip, both these two methods significantly correlated with the mechanical withdrawal threshold and had the predictive power for the mechanical hypersensitivity. In summary, these findings imply that both surviving and injured nerves are necessary for evoked neuropathic pain. In addition, both of these assessments have the predictive effect to be used as a diagnostic and prognostic biomarker for neuropathic pain.

並列關鍵字

Chronic constriction injury ； Cutaneous nerve fiber ； Intravital two-photon fluorescence microscopy ； Nav1.8 ； Neuropathic pain

參考文獻

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