Oxygen monitoring during 5-aminolaevulinic acid induced photodynamic therapy in normal rat colon - Comparison of continuous and fractionated light regimes
Oxygen monitoring during 5-aminolaevulinic acid induced photodynamic therapy in normal rat colon - Comparison of continuous and fractionated light regimes
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DOI：
10.1016/s1011-1344(00)00120-2
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发表时间：
2000-11-01
影响因子：
5.4
通讯作者：
Bown, SG
中科院分区：
文献类型：
--
作者：
Curnow, A;Haller, JC;Bown, SG
目前，5-氨基乙酰丙酸（ALA）诱导的原卟啉IX（PPIX）用于光动力疗法（PDT）的临床使用受到最大耐受口服ALA剂量（60 mg/kg）的限制。已经尝试在不增加ALA的施用剂量的情况下增强这种治疗方式。其中一种方法是通过光剂量分级，其中照射在特定点中断一段短时间。这可以产生高达三倍以上的坏死比相同的光剂量提供没有中断。应用氧微电极研究了ALA光动力疗法（ALA PDT）中连续和分次光照对正常Wistar大鼠结肠氧含量的影响。一个快速下降的p（O2）发生接近照射纤维的光剂量开始。与分馏制度，部分恢复p（O2）中观察到在黑暗的时间间隔，这是逆转后不久，第二个轻馏分开始。我们已经表明，当光剂量被分割时，与采用连续照明时相比，治疗部位处的组织氧水平受到不同的影响。这一因素至少可以部分解释这两种治疗方案结果的差异。此外，氧测量可能被证明是一个有用的方法来监测PDT治疗，如果他们可以预测组织是否可能是可行的治疗后。(C)2000 Elsevier Science B. V.保留所有权利。
Currently, the clinical use of 5-aminolaevulinic acid (ALA) induced protoporphyrin IX (PPIX) for photodynamic therapy (PDT) is Limited by the maximum tolerated oral ALA dose (60 mg/kg). Attempts have been made to enhance this treatment modality without increasing the administered dose of ALA. One way to do this is through light dose fractionation, where the irradiation is interrupted at a particular point for a short period of time. This can produce up to three times more necrosis than with the same light dose delivered without a break. An oxygen microelectrode was employed to study the effect of continuous and fractionated light regimes on the level of oxygen in the colon of normal Wistar rats during ALA PDT. A rapid decline in p(O2) occurred close to the irradiation fibre as soon as the light dose commenced. With the fractionated regime, a partial recovery in p(O2) was observed during the dark interval which was reversed soon after the second light fraction commenced. We have shown that the level of tissue oxygen at the treatment site is affected differently when the Light dose is fractionated, than when continuous illumination is employed. This factor may at least partially explain the difference in outcome of these two treatment regimes. Further, oxygen measurements might prove to be a useful way of monitoring PDT treatments if they can predict whether tissue is likely to be viable following treatment. (C) 2000 Elsevier Science B.V. All rights reserved.