贝伐单抗联合手术切除后光动力疗法治疗大鼠颅内胶质瘤的实验研究

Combination therapy with Bevacizumab and PDT after surgical resection in rats with orthotropic glioma

目的观察贝伐单抗联合手术切除后光动力疗法(PDT)治疗大鼠颅内胶质瘤的效果并探讨其机制。方法 64只Fischer 344大鼠颅内种植9L胶质瘤细胞后,随机分为对照组、手术组(显微手术切除肿瘤)、手术+PDT组(手术切除肿瘤后即行80 J/cm2PDT照射术区)和手术+PDT+贝伐单抗(贝伐单抗+手术切除肿瘤后即行80 J/cm2PDT照射术区)组。9L细胞种植7 d后治疗组接受相应的治疗;种植14 d后每组随机选取6只大鼠处死,行HE染色检测颅内肿瘤的生长情况,用Western blotting检测肿瘤周围VEGF的表达。其余40只大鼠自然死亡,记录生存期。结果对照组、手术组、手术+PDT组和手术+PDT+贝伐单抗组大鼠种植9L细胞后的平均生存时间为(15.9±1.5)d、(33.3±2.7)d、(43.4±3.3)d和(58.7±4.2)d,各组间的平均生存时间差异有统计学意义(P=0.000)。9L细胞种植14 d后,3个治疗组中的肿瘤绝大部分被切除,肿瘤体积明显减少(P=0.000)。手术组术后残腔周围浸润灶的数量和面积与对照组相比差异无统计学意义,但手术+PDT组和手术+PDT+贝伐单抗组的浸润灶数量极少,浸润灶面积也小,与对照组和手术组相比差异有统计学意义(P=0.000)。与对照组比较,手术组和手术+PDT+贝伐单抗组的VEGF表达明显降低(P=0.000),但手术+PDT组VEGF的表达明显高于手术组和手术+PDT+贝伐单抗组,差异具有统计学意义(P=0.000)。结论手术切除脑胶质瘤后行PDT治疗可以杀灭术后残腔周围的肿瘤浸润灶,再辅以贝伐单抗的治疗,能够抑制PDT诱导新生血管形成的副作用,从而明显提高脑胶质瘤的治疗效果。

【Objectives】 To investigate the effect of Bevacizumab combine with photodynamic therapy（PDT） after surgical resection in Fischer 344 rats with orthotropic glioma and explored its mechanisms.【Methods】Sixty-four Fischer 344 rats were implanted 9L cells in brain.Rats were randomly divided into 4 groups on day 7 after implantation： control,surgery（near-total resection of intracranial tumors）,surgery ＋ PDT（80 J/cm 2 ALA-PDT after surgery） and surgery ＋ PDT ＋ Bevacizumab,and received the appropriate treatment.Six rats in every group were sacrificed on day 7 after implantation,and tumor sizes as well as infiltrated tumor foci were detected by H.E.staining.The expressions of vascular endothelial growth factor（VEGF） in brain around tumor were detected by Western blotting.Other rats were observed survival.【Results】 The survival time after 9L cells implantation of control,surgery,surgery ＋ PDT and surgery ＋ PDT ＋ Bevacizumab was（15.9 ± 1.5） d,（33.3 ± 2.7） d,（43.4 ± 3.3） d and（58.7 ± 4.2） d,respectively.There were significant differences between every two groups in survival time（P =0.000）.On day 7 after implantation,different treatment could significantly reduce tumor size（P =0.000） compared with control group,because most parts of tumor were removed in three treatment groups.there were fewer invasive foci surrounded the tumor mass in surgery ＋ PDT and surgery ＋ PDT ＋ Bevacizumab group than in control and surgery group（P =0.000）.Compared with control group,VEGF expression in surgery and surgery ＋ PDT ＋ Bevacizumab group（P =0.000）.However,VEGF expression in surgery ＋ PDT was significantly higher than it in surgery and surgery ＋ PDT ＋ Bevacizumab group（P =0.000）.【Conclusion】 Bevacizumab combines with PDT after surgical resection significantly improve the glioma therapeutic effect because PDT can kill infiltrating tumor lesions around postoperative residual cavity,and then Bevacizumab can suppress the side effects of PDT,which induced angiogenesis.