CGS26303 一種內皮素轉化酶抑制劑，對於老鼠外傷性 脊髓損傷的效果

The Effects of CGS26303, an Endotheline-Converting Enzyme Inhibitor on Rats with Traumatic Spinaal Cord Injury

蘇裕峰(Yu-Feng Su)

指導教授 ： 關皚麗

共同指導教授 ： 陳世杰(Shih-Chieh Chen)

高雄醫學大學/醫學院/醫學研究所/碩士(2007年)

摘要

CGS26303，一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腔出血與大腦中動脈阻塞所引起的神經傷害，具有神經保護的功能。近來的研究更指出，在老鼠脊髓缺血再灌流傷害(ischemia-reperfusion)的動物實驗模式中，CGS26303 對於脊髓亦有神經保護的功能。本論文研究目的是探討CGS 26303 在老鼠外傷性脊髓損傷的動物實驗模式中，是否相同的神經保護效果。我們的動物模式是使用2 French 的Fogarty 導管，自第三至第四腰椎間穿入，向上達第6 胸椎的高度後，打入0.2 ml 的空氣，壓迫脊髓達10 分鐘。在手術後以量表評估其神經運動功能。實驗的結果顯示，給予CGS 26303 治療的動物，與給予載體安慰劑的對照組比較，在脊髓損傷後的第一天及第三天，其運動功能障礙指數皆有顯著下降，下肢半身癱瘓比例也有顯著的差異。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，eNOS（endothelial nitric oxide synthase）和iNOS(inducible nitric oxide synthase）的mRNA 基因表現。結果顯示，脊髓損傷後， eNOS 及iNOS 的mRNA 基因表現皆有顯著的上升; 給予CGS26303 治療後， eNOS 的基因表現與載體安慰劑組比較，有顯著的下降，而iNOS 的基因表現雖有降低的趨勢，但未達統計上的顯著。結論是，在老鼠外傷性脊髓損傷的動物實驗模式中，給予CGS26303治療的老鼠，保有的較佳的運動功能及較低的半身癱瘓比例，有保護脊髓的效果; eNOS 與iNOS 的mRNA 基因表現可能與之有所關聯。

關鍵字

脊髓損傷 ； CGS26303 ； 內皮素轉化酶抑制劑 ； 一氧化氮合成酶

並列摘要

Background: Endothelin-1 (ET-1) has been implicated in many neurological diseases, including subarachnoid hemorrhage(SAH) and cerebral ischemia. Our previous studies demonstrated well that CGS 26303, an endothelin-converting enzyme (ECE) inhibitor, possessed beneficial effects for the treatment of SAH-induced vasospasm and transient middle cerebral artery occlusion. Previous study also showed plasma ET-1 and ET-3 are low in the normal, uninjured CNS but significantly increase following spinal cord trauma. The study on endothelin receptor expression in the normal and injured spinal cord revealed that blocking endothelin receptor may reduce the resulting ischemia and astrogliosis, and increase neuronal survival, regeneration and function. Recently, our group revealed the functional neuroprotective effect of CGS 26303, on ischemic-reperfusion spinal cord injury in rats. However, the potential role of ECE inhibitor in traumatic spinal cord injury has not been evaluated. In this study, we investigated the effects of CGS26303 on the locomddotor function and the expression of inducible nitric oxide synthases (iNOS) and endothelial nitric oxide synthases (eNOS) in rats subjected to traumatic spinal cord injury surgery. Material and Methods: 35 Sprague-Dawley (SD) rats were randomized to five groups: (1) Healthy control (2) Sham operated (3) Traumatic spinal cord injury with Fogarty catheter(2 French) passing from the lumbar spine (L3-4) to the level of thoracic spine (T6-7). The Fogarty catheter then was inflated with room air, 0.2ml and lasted 10 minutes. (4)Spinal cord injury with treatment of CGS 26303, 10mg/kg, intravenously once a day (5) Spinal cord injury with treatment of vehicle. The motor deficit index was evaluated and the mRNA expression of eNOS and iNOS of the spinal cord were investigated with reverse transcription polymerase chain reaction (RT-PCR). Results: The motor deficit index(MDI) in the group with treatment of CGS26303 significant decreased on the day 1 and day 3 after the traumatic spinal cord injury. The mRNA expression of eNOS and iNOS after the spinal cord injury both increased significantly. The mRNA expression of eNOS in the group of CGS26303 treatment decreased significantly, comparing with that in the group of vehicle. The expression of iNOS trended to decreased without significance statistically. Conclusion: The results suggested that CGS 26303 had neuroprotective effects on the rats with traumatic spinal cord injury. The mRNA expression of eNOS and iNOS maybe related with the effect.

並列關鍵字

Spinal cord injury ； CGS26303 ； endothelin-converting enzyme inhibitor ； NOS

參考文獻

1.Allen, A.R., Surgery of experimental lesions of spinal cord equivalent to crush of fracture dislocation of spinal column. A preliminary report. J Am Med Assoc, 1911. 57: p. 878-880.

2.Ao, Q., et al., Protective effects of extract of Ginkgo biloba (EGb 761) on nerve cells after spinal cord injury in rats. Spinal Cord, 2006. 44(11): p. 662-7.

3.Behrmann, D.L., et al., Spinal cord injury produced by consistent mechanical displacement of the cord in rats: behavioral and histologic analysis. J Neurotrauma, 1992. 9(3): p. 197-217.

4.Benton, R.L., et al., Intraspinal application of endothelin results in focal ischemic injury of spinal gray matter and restricts the differentiation of engrafted neural stem cells. Neurochem Res, 2005. 30(6-7): p. 809-23.

5.Chang, C.Z., et al., Neuroprotective Effect of CGS 26303, an Endothelin-converting Enzyme Inhibitor, on Transient Middle Cerebral Artery Occlusion in Rats. J Cardiovasc Pharmacol, 2004. 44: p. S487-S489.