CGS 26303，一種內皮素轉化酶抑制劑，對於老鼠脊髓缺血再灌流傷害的神經保護效果之研究

Neuroprotective effect of CGS 26303, an endothelin- converting enzyme inhibitor, on the ischemia-reperfusion spinal cord injury in rats

陳太乙(Tai-I Chen)

指導教授 ： 關皚麗教授

高雄醫學大學/醫學院/醫學研究所/碩士(2006年)

https://doi.org/10.6832/KMU.2006.00100

摘要

缺血再灌流傷害（ischemia-reperfusion injury）是造成脊髓受傷的重要因素，由於胸腰椎脊髓之血液供應主要來自於胸腹主動脈，在胸腹主動脈手術常見因脊髓缺血而導致下肢癱瘓之嚴重併發症。
近年來的研究已逐漸了解缺血再灌流傷害之致病機轉，其中包括過氧化物、自由基與內皮素-1（endothelin-1，ET-1）等。ET-1是一種血管收縮素，已經被證實與許多組織、器官的缺血再灌流傷害有密切的關係，其中包含神經系統的疾病，例如蜘蛛網膜下出血與腦缺血性疾病，惟ET-1是否會造成脊髓缺血再灌流傷害仍未被證實。
先前的研究指出，一種內皮素轉化酶抑制劑（endothelin-converting enzyme inhibitor），CGS 26303，能夠減輕蜘蛛網膜下出血與大腦中動脈阻塞所引起的神經傷害。本論文研究目的是想藉由動物實驗，了解CGS 26303是否有保護脊髓的效果，為探討此問題，在這次的實驗中，我們選擇老鼠的動物實驗模式，模擬術中主動脈截流的過程並導致脊髓傷害的現象，利用這個動物實驗模式，在對老鼠進行十五分鐘的短暫性主動脈截流以誘發脊髓缺血性傷害。在對主動脈截流之前三十分鐘，從靜脈注射CGS 26303來保護脊髓。實驗結果指出，CGS 26303的確有保護脊髓的效果，不但降低半身癱瘓的發生率，而且也減輕運動功能缺損的嚴重度；另外以半定量反轉錄核酸聚合酶連鎖反應（reverse transcription polymerase chain reaction，RT-PCR）的方式來定量脊髓中原血紅素氧化酶-1（heme oxygenase-1，HO-1）mRNA，eNOS（endothelial nitric oxide synthase）、nNOS（neuronal nitric oxide synthase）和iNOS（inducible nitric oxide synthase）的表現。
實驗的結果顯示，給予CGS 26303的治療組動物保有較佳的運動功能與較低的下肢半身癱瘓比例（和給予生理食鹽水的對照組相比）；HO-1 mRNA的表現程度也是治療組明顯高於對照組與控制組（sham operation）。但是iNOS在三個族群均偵測不到，而且eNOS和nNOS等基因表現與對照組沒有不同。所以，我們的研究顯示CGS 26303可以保護脊髓、減少缺血再灌流的傷害，其機轉可能與活化大量的HO-1酵素有關。

關鍵字

內皮素轉化酶抑制劑 ； 缺血再灌流傷害 ； 脊髓損傷

並列摘要

Endothelin-1 (ET-1) has been implicated in many neurological diseases, including subarachnoid hemorrhage and cerebral ischemia. ET-1 is also proved to deteriorate the ischemia-reperfusion injury in many organs yet the spinal cord was not.Our previous studies demonstrated the endothelin-converting enzyme (ECE) inhibitor, CGS26303, possessed beneficial effects for the treatment of SAH and transient middle cerebral artery occlusion. In this study, we investigated the neuroprotective effect of CGS 26303 on locomotor function of rats and mRNA expression of heme-oxygenase-1 (HO-1) using semi-quantitative reverse transcription-polymerase chain reaction after 15 minutes spinal cord ischemia. The results showed rats subjected to spinal cord ischemia with pretreatment by CGS 26303 appeared a significant in preservation in the locomotor function and decreasing the paraplegia rate at Day 1 and 3 as compared with saline-treated group. Furthermore, the rats pretreated with CGS 26303 showed a significant increase in the levels of HO-1 mRNA expression at Day 3 in contrast with the rats pretreated with saline and sham operation group after spinal cord ischemia. These results demonstrated that CGS 26303 may hold the promising neuroprotection in the spinal cord ischemia-reperfusion injury and result from an adaptive mechanism involved by HO-1 overexpression.

並列關鍵字

endothelin-converting enzyme inhibitor ； CGS 26303 ； ischemia- reperfusion injury ； paraplegia ； spinal cord injury ； heme-oxygenase

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