Fractionated illumination for oesophageal ALA-PDT: Effect on blood flow and PpIX formation
Fractionated illumination for oesophageal ALA-PDT: Effect on blood flow and PpIX formation
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DOI：
10.1007/pl00011331
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发表时间：
2001-01-01
影响因子：
2.1
通讯作者：
van Hillegersberg, R
中科院分区：
文献类型：
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作者：
van den Boogert, J;van Staveren, HJ;van Hillegersberg, R
研究了633nm分次照射5-氨基乙酰丙酸（ALA）光动力学疗法（PDT）对正常大鼠食管的作用。分次照射可以通过两种方式增强PDT效应：（a）延迟ALA-PDT诱导的血管关闭或血管收缩的松弛，和（B）使用在黑暗间隔期间产生的新形成的原卟啉TX（PpIX）。将40只大鼠随机分配到两组，每组20只动物。为了研究血管效应，在第1组中，在口服ALA（200 mg/kg）后3 h进行633 nm（100 mW/cm）的照射，连续照射20 J/cm扩散器长度（n = 5）或以150 s间隔分次照射2 x 107 J/cm（n = 5），5只动物作为对照。用激光多普勒流量计测量洪水流量。为了研究更新的PpIX形成的效果，第2组中的动物在ALA后3h以20 J/cm（n = 5）或40 J/cm（n = 5）连续照射或间隔3h分次照射2 × 20 J/cm（n = 5），5只动物作为对照。在所有动物中，在照明期间测量体内注量率和PpIX荧光，并在PDT后48 h处死动物。ALA-PDT未引起任何显著的血管收缩。第1组中的荧光测量和剂量测定结果在连续照射或以150 s间隔分次照射的动物之间没有差异。在组2中，在3小时的黑暗间隔期间，PpIX荧光增加，并在第二次照明期间被漂白。在3 h黑暗间隔期间，组织光学特性发生变化，导致体内注量率降低（p ≤ 0.001）。分割未导致更多食管损伤。得出结论，ALA-PDT中照明期间的150 s间隔不会增加食管血流量。在3小时的间隔期间，形成新的PpIX。在本研究中，使用短或长时间间隔的分次照射并没有导致更多的损伤。因此，该研究没有显示出使用分次光递送改善PDT效果的证据。
The effect of fractionating the 633 nm illumination of 5-aminolaevulinic (ALA)-based photodynamic therapy (PDT) of the normal rat oesophagus was studied. Fractionation of the illumination could enhance the PDT effect in two ways: (a) delay of the vascular shutdown or relaxation of the vasoconstriction induced by ALA-PDT and (b) use of newly formed protoporphyrin TX (PpIX), produced during the dark interval. Forty rats were randomly allocated to two groups of 20 animal each. To study vascular effects, in group 1 illumination with 633 nm (100 mW/cm) was performed at 3 h after oral ALA administration (200 mg/kg) either continuously with 20 J/cm diffuser length (n=5) or fractionated 2 x 10 J/cm with a 150 s interval (n=5), five animals served as controls. Flood flow was measured with a laser Doppler flowmeter. To study the effect of renewed PpIX forming, animals in group 2 were illuminated continuously at 3 h after ALA with 20 J/cm (n=5) or 40 J/cm (n=5) or fractionated 2 x 20 J/cm with a 3 h interval (n=5), five animals served as controls. In all animals the in vivo fluence rate and PpIX fluorescence were measured during illuminations and animals were killed at 48 h after PDT.ALA-PDT did not cause any significant vasoconstriction. Fluorescence measurements and dosimetric results in group 1 did not differ between animals illuminated continuously or fractionated with a 150 s interval. In group 2, during a 3 h dark interval, PpIX fluorescence increased and was bleached during the second illumination. The tissue optical properties changed during the 3 h dark interval, resulting in a lower in vivo fluence rate (p less than or equal to 0.001). Fractionation did not result in more oesophageal damage. It was concluded that a 150 s interval during illumination in ALA-PDT does not increase oesophageal blood flow. During an interval of 3 h new PpIX is formed. In the present study, fractionated illumination using short or long time intervals did not result in more damage. Thus, this study shows no evidence for improved PDT effect with fractionated light delivery.