過去的研究發現台灣眼鏡蛇心臟毒蛋白A3進入H9c2心肌細胞的行為會受到膽固醇的影響，與文獻報導過的一些分子進入細胞的行為相反﹙70、74﹚。因此本論文利用調整細胞膜膽固醇濃度，以共軛焦顯微鏡及細胞毒性測試觀察心臟毒蛋白A3的機制表現，並藉由抑制dynamin參與的胞飲作用，推測心臟毒蛋白A3可能的進入細胞之途徑。結果顯示心臟毒蛋白A3進入細胞與細胞膜膽固醇濃度有關，心臟毒蛋白A3進去的數量隨著膽固醇濃度的減少而增加，細胞毒性也隨著增加，因此細胞膜膽固醇濃度除了影響心臟毒蛋白A3進入細胞的表現也影響其細胞毒性。另外，抑制dynamin參與的胞飲作用後對心臟毒蛋白A3進去細胞的表現沒有明顯的影響，排除了心臟毒蛋白A3進入細胞是經由籠型蛋白及細胞窖的可能性。由以上研究結果，心臟毒蛋白A3進入細胞的機制是對膽固醇敏感而且不需要dynamin參與的過程。

It has recently been shown that CTX A3 internalizes into H9c2 cell (Chia-Hui Wang, phD thesis; Jin-Lang Lin, Master thesis). It is a cholesterol-sensitive process which is different from the other reported cases. In my studies, confocal microscopy and cytotoxicity assay were employed to observe the behavior of CTX A3 after modifying the concentration of cholesterol on cell plasma membrane. Dynasore, the specific inhibitor of dynamin-dependent endocytosis, was used to investigate the possible mechanism involved in the internalization of CTX A3. The results showed that the internalization of CTX A3 was cholesterol concentration- dependent and dynamin-independent process, and the cytotoxicity of CTX A3 is cholesterol-sensitive. It was suggested that the cytotoxicity of CTX A3 was correlated with the internalization of CTX A3.

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