| 摘要: | 利用本實驗室發展出的不連續5-Bromodeoxyuridine處理方法，以研究 cyclophosphamide，殺丹 (saturn)，丁基拉草 (butachlor)及甲氧基護古(chlomeoxynil) 對牛蛙(Rana atesbeiana)的遺傳毒性及細胞毒性的影響。Cyclophosphamide為一種已 知的抗癌且是致癌劑，saturn,butachlor及chlomeoxynil為臺灣水田最常用的三種殺 草劑。Cyclophosphamide在低劑量下，所誘導的姊妹染色分體交換頻率(sister chromatid exchange frequencies,SCE)是與劑量的增加成正比，Saturn及butachlor只在 危害動物生命的高劑量下，才會誘導SCE的產生。根據細胞複製指數 (replicative indices)的分析試驗，cyclophosphamide及butachlor只會稍微延緩細胞週期的時間。 然而satlirn卻會顯著降低牛蛙骨髓細胞的複製指數。在所測驗的劑量下， chlomeoxynil不會造成SCE顯著增加，但會延緩細胞分裂週期。比較幾個藥品的最 低有效劑量,cyclophosphamide所誘導的SCE為saturn的22倍，為butachlor的157倍。 本研究結果顯示由本實驗室所發展出來的牛蛙體內SCEs分析方法，可用來偵測環 境中化學物質的遺傳毒性，並有助農藥毒性的評估。
A discontinuous 5 - Bromodeoxyuridine administration method developed byour lab, was utilized to detect the genotoxic and cytotoxic effects ofcyclophosphamide, saturn, butachlor, and chlomethoxynil in Rana catesbeiana.Cyclophosphamide, a well known antitumor agent and a carcinogen, yields a dose dependent increase in the SCEs frequency. Saturn and butachlor induced SCEsin bullfrogs only at a dose which affected the viability of these animals. Analysisof the replicative indices showed that cyclophosphamide and butachlor caused aslight cell - cycle delay whereas saturn caused a dose dependent and significantdecrease in replicative index. Chlomethoxynil did not show any significantincrease in SCEs over baseline at the dosage tested. However a delay in cell cyclewas observed by chlomethoxynil. The present study demonstrates that in vivo SCE method in bullfrogs can be used as a monitoring system for the assessment of environmental genotoxic chemicals. |
