放射联合重组人血管内皮抑制素致心肌纤维化的作用机制

Mechanism of radiation combined with recombinant human endostatin in inducing myocardial fibrosis

目的建立实验动物模型探索放射性心肌纤维化的作用机制,验证重组人血管内皮抑制素可通过TGF-β1、Smad2、Smad3信号通路加重放射性心肌纤维化的过程.方法60只SD成年雄性大鼠随机分为25 Gy照射组、内皮抑制素6mg/kg组、内皮抑制素12 mg/kg组、25 Gy照射+内皮抑制素6mg/kg组、25Gy照射+内皮抑制素12 mg/kg组和对照组,分别在干预后1、3个月每组随机处死5只大鼠取心肌组织完成HE染色了解病理学改变,Masson染色了解纤维化程度,qPCR及Western Blot检测TGF-β1、Smad2、Smad3、Collagen-Ⅰ基因及蛋白表达.结果干预后3个月,25 Gy照射组、25 Gy照射+内皮抑制素(6、12mg/kg)组与对照组比较Masson染色见胶原沉积明显增加,TGF-β1、Smad2、Smad3、Collagen-Ⅰ蛋白及基因表达增加.结论给予大鼠总物理剂量为25Gy的照射,可诱导放射性心肌纤维化的发生.TGF-β1、Smad2信号通路是介导放射联合重组人血管内皮抑制素致心肌纤维化损伤的共同信号通路.

Objective The experimental animal model was established to unravel the mechanism of radiation-induced myocardial fibrosis and validate the role of recombinant human endostatin in aggravating the process of radiation-induced myocardial fibrosis via the TGF-β1,Smad2 and Smad3 signaling pathways.Methods Sixty male adult Sprague-Dawley rats were randomly divided into the following groups:radiotherapy(RT)25 Gy,recombinant human endostatin(RE)6 mg/kg,RE 12 mg/kg,RT 25 Gy+RE 6 mg/kg,RT 25 Gy+RE 12 mg/kg and blank control groups.Five rats were sacrificed in each group at 1 and 3 months after interventions.The myocardial tissues were collected.The pathological changes were observed by Hematoxylin and eosin staining.The degree of fibrosis was assessed by Masson trichrome staining.The expression levels of TGF-β1,Smad2,Smad3 and Collagen-I mRNA and protein were quantitatively measured by real-time PCR and Western blotting.Results At 3 months after intervention,Masson trichrome staining revealed that the collagen deposition in the RT 25Gy and RT 25Gy+RE(6 and 12 mg/kg)groups was more significant than that in the control group.In addition,The expression levels of TGF-β1,Smad2,Smad3 and Collagen-I mRNA and protein in these groups were significantly up-regulated compared with those in the control group.Conclusions Radiation with a total physical dose of 25 Gy can induce myocardial fibrosis in the SD rat models.TGF-β1 and Smad2 signaling pathways are the common signaling pathways of myocardial fibrosis induced by radiation combined with recombinant human endostatin.