內側視丘核區於大鼠坐骨神經痛之發展與持續時期之重要性

Importance of the medial thalamus in the development and maintenance of neuropathy of spared nerve injured rats

洪瑋辰(Wei-Chen Hung)

指導教授 ： 嚴震東

國立臺灣大學/生命科學院/動物學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.01836

摘要

視丘神經核基於特性不同可分為內側及外側系統。內側視丘核區一直以來被認為對於長期疼痛具有重要影響，然而在神經痛當中扮演的角色還未明瞭。此研究的目的為探討內側視丘核區永久性破壞對於大鼠神經痛的影響。我們選擇大鼠坐骨神經分支選擇結紮切斷模型(spared nerve injury model, SNI)。大鼠在手術後會產生許多疼痛相關的行為，包含機械性及冷異常性疼痛、熱痛覺過敏和自發性疼痛。在第一個實驗，先去檢測內側視丘核區的破壞是否會造成大鼠在行為上的改變。我們發現大鼠在接受內側視丘核區破壞的手術後，會造成熱及冷痛覺過敏。這種現象會在手術後一星期左右逐漸消失。第二個實驗，我們檢測內側視丘核區是否參與神經痛的維持。大鼠在神經痛手術後1星期，兩側的內側視丘神經核接受NMDA注射造成其永久性破壞。再經由連續一個月測量疼痛行為的改變，觀察內側視丘神經核在神經痛所扮演的角色。結果顯示，內側視丘核區永久性破壞並不會對機械性異常性疼痛和自發性疼痛產生顯著的影響。然而，冷異常性疼痛卻在永久性破壞後8天內顯著性的下降。對熱痛覺過敏顯著的下降更長達21天。第三個實驗主要是檢測內側視丘核區是否參與神經痛的發展。大鼠先接受內側視丘核區破壞的手術，使其休息14天後再給予神經痛手術。被破壞內側視丘核區的大鼠在熱痛覺過敏的發展顯著的降低，並不會對機械性和冷異常性疼痛及自發性疼痛產生顯著的影響。從結果顯示，內側視丘神經核對於熱痛覺過敏的發展及持續扮演著很重要的角色。

關鍵字

神經痛 ； 坐骨神經分支選擇結紮切斷模型 ； 內側視丘核區 ； 熱痛覺過敏 ； 異常性疼痛 ； N-甲基-D-天冬氨酸傷害

並列摘要

Neuropathic pain is a type of chronic pain caused by damage in the somatosensory nerve system. The major syndromes of neuropathic pain are spontaneous pain, allodynia, and hyperalgesia. Medial thalamus is a part of medial pain pathway. Previous studies show that medial thalamus (MT) play a specific role in chronic pain, and express abnormal hyperactivity in the neuropathic patients or rats. The involvement of the MT in the modulation of neuropathic pain is still unclear. All rats were tested for the pain-related behaviors, including hyperalgesia (heat), allodynia (mechanical and cold) and spontaneous pain (paw withdrawal).
In first experiment, the rats received bilateral NMDA lesion. Our data show mechanical allodynia and spontaneous pain did not change by MT lesion. Animals with lesions would have induced cold and heat hypersensitive about 1 week. In second experiment, we tested the effects of the lesion of the medial thalamic system on the allodynia and hyperalgesia in neuropathic rats. The rats with lesions would have decreased cold and heat hypersensitive of the neuropathic manifestations up to 1 week. The latency of radiant heat test was significantly prolonged lasted more than 21 days. In third experiment, the lesion-induced cold and heat hypersensitive decreased 14 days after MT lesion. No differences between sham and lesion were detected. Therefore, the rats induced mononeuropathy following 14 days after MT lesion. MT lesion partially prevents thermal hypersensitivity of SNI rats. The results suggest that MT may play a role in thermal allodynia and cold hyperalgesia, but not in mechanical allodynia and spontaneous pain.

並列關鍵字

neuropathic pain ； spared nerve injury ； medial thalamus ； thermal hyperalgesia ； allodynia ； N-methyl-D-aspartic acid (NMDA) lesion

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