贝伐单抗对ALA—PDT诱导的新生血管形成和胶质瘤生长的影响

探讨贝伐单抗对低剂量5-氨基乙酰丙酸（5-Aminolevulinicacid，ALA）介导的光动力学疗法（photodynamic therapy，PDT）诱导的脑组织新生血管形成和U87脑胶质瘤生长的影响。通过将裸小鼠随机分为对照组、ALA．PDT预处置组（ALA：2．3×10-3mol／kg，能量密度：10J／cm2）、贝伐单抗预处置组（1．6×10-5mol／kg）和联合预处置组（ALA—PDT＋贝伐单抗），并接受相应处置。第10d，检测PDT照射及相应区域内新生血管形成和VEGF表达并种植U87脑胶质瘤细胞，21d后观察肿瘤体积。与对照组比较，低剂量ALA-PDT预处置后新生血管增多、VEGF表达增高，肿瘤体积增大，这些变化在联合预处置组被抑制；贝伐单抗预处置组的血管形态和VEGF表达虽无明显变化，但肿瘤体积减小。研究结果表明低剂量ALA-PDT可通过刺激VEGF表达诱导照射区新生血管形成，这种微环境的改变有利于U87胶质瘤细胞生长，但这些作用可被贝伐单抗所抑制。

Effect of Bevacizumab on Angiogenesis and Glioma Growth Induced by Low Dose of ALA-PDT

To evaluate the effects of 5-Aminolevulinic acid-mediated photodynamic therapy （ALA-PDT） with low dose （ 10 J/cm2 ） on intracranial angiogenesis and glioma growth in nude mice and the influence of Bevaeizumab on these changes. Nude mice were divided into 1 ） control, 2） ALA-PDT （ALA：2.3 x 10.3 mol/kg,dose： 10 J/cm2）, 3 ） Bevaeizumab （ 1.6 x 10.5 mol/kg and 4） combination （ PDT ＋ Bevacizumab） pretreated groups. After 10 days of pretreatment, angiogenesis and VEGF in brain were measured, and then mice were implanted intracerebral U87 glioma. Tumor volume was analyzed after 21 days. Compared with control, angiogenesis, VEGF expressions and tumor volume in ALA- PDT pretreated group significantly increased which could be inhibited by Bevacizumab. However, there was no difference between control and Bevacizumab pretreated groups except that tumor volume in Bevacizumab pretreated group was smaller than control. ALA-PDT with low dose can induce angiogenesis mediated by VEGF in brain which is helpful to glioma growth; however, Bevacizumab has an inhibitive effect on these changes.