血卟啉单甲醚光动力疗法预防兔颈动静脉内瘘静脉内膜增生

Photodynamic therapy with hematoporphyr in monomethyl ether alleviates venous neointimal hyperplasia in arteriovenous fistulas in rabbits

目的研究血卟啉单甲醚光动力疗法(hematoporphyrin monomethyl ether,HMME-PDT)对兔颈动静脉内瘘静脉内膜增生(venous neointimal hyperplasia,VNH)的影响。方法建立兔颈总动脉-颈静脉端侧吻合动静脉内瘘(arteriovenous fistulas,AVF)模型32例,按随机数字表法分为4组,每组8只:对照组、单纯光敏剂组、单纯光照组、光动力治疗组。术后彩色多普勒超声检查吻合口通畅情况及血流频谱,术后30 d截取AVF吻合口静脉端血管组织,利用HE染色、Masson染色观测各组静脉内中膜厚度及管腔面积;利用免疫组织化学染色检测增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)、α-SMA、Caspase3的表达分布;利用Western blot技术检测PCNA、α-SMA、Caspase3、Caspase9、Bax、Bcl-2蛋白的表达量。结果HE染色显示光动力治疗组血管静脉内中膜厚度明显减小,Masson染色显示光动力治疗组管腔面积较其余3组明显增大(P<0.05)。免疫组织化学染色统计结果表明光动力治疗组PCNA、α-SMA表达较其余3组明显降低(P<0.05),Caspase3表达较其余3组明显增加(P<0.05)。Western blot结果显示光动力治疗组PCNA、Bcl-2、ɑ-SMA表达以及Bcl-2/Bax指数较其余3组明显增降低(P<0.05),Caspase3、Caspase9、Bax表达较其余3组明显增加(P<0.05)。结论HMME-PDT能够明显减轻兔AVF内中膜增生。HMME-PDT通过Bcl-2/Bax凋亡途径促进血管平滑肌细胞(VSMC)凋亡,抑制其增殖,从而达到抑制动静脉内瘘静脉内膜增生的效果。

Objective To observe the effects of photodynamic therapy(PDT)with hematoporphyrin monomethyl ether(HMME)on venous neointimal hyperplasia(VNH)in arteriovenous fistulas(AVFs)in rabbits.Methods We established models of AVF by end-to-side anastomosis of the common carotid artery to the jugular vein in 32 adult rabbits,which were randomized into 4 groups(n=8),including a control group without any intervention,an HMME group with HMME treatment only,a light illumination(without HMME)group,and a HMME-PDT group receiving both the photosensitizer and light illumination.Color Doppler ultrasound was used to detect the blood flow after the operation.At 30 d after the operation,the jugular vein tissue was collected for assessing VNH and measurement of the lumen area using HE and Masson staining and for detecting the expression of proliferating cell nuclear antigen(PCNA)andɑ-smooth muscle actin(ɑ-SMA)using immunohistochemistry;Western blotting was performed to analyze the expression of proliferating cell nuclear antigen(PCNA),Bcl-2,ɑ-SMA,Caspase3,Caspase9 and Bax.Results The jugular vein tissues showed significantly lessened VNH and increased lumen area in HMME-PDT group compared with the other groups(P<0.05).The results of immunohistochemistry showed that the expression of PCNA andɑ-SMA was decreased and Caspase3 expression was increased significantly in HMME-PDT group compared with the other groups(P<0.05).Western blotting results showed that among the 4 groups,the expression of Caspase3,Caspase9 and Bax were the highest(P<0.05)while those of PCNA,Bcl-2,ɑ-SMA and Bcl-2/Bax ratio the lowest in HMME-PDT group(P<0.05).Conclusion HMME-PDT can effectively reduce VNH in AVFs in rabbits by suppressing proliferation and promoting apoptosis of the vascular smooth muscle cells via the Bcl-2/Bax pathway.