重组人促红细胞生成素联合骨髓间充质干细胞移植治疗脓毒症大鼠心肌损伤

Recombinant human erythropoietin combined with bone marrow mesenchymal stem cell transplantation for myocardial damage in sepsis rats

背景:相关研究表明促红细胞生成素及骨髓间充质干细胞均对心肌凋亡有一定影响,但两者联合应用治疗脓毒症相关性心肌损伤少见报道。目的:观察骨髓间充质干细胞移植联合腹腔内注射促红细胞生成素对脓毒症大鼠心肌细胞病理学改变及细胞凋亡的影响。方法:选用SD大鼠50只,随机数字表法均分为5组(n=10),应用盲肠结扎穿孔术建立脓毒症大鼠模型。骨髓间充质干细胞组建模后即刻尾静脉输注异体间充质干细胞;促红细胞生成素组建模后即刻腹腔内注射促红细胞生成素;促红细胞生成素+细胞移植组两者联合应用;模型组行盲肠结扎穿孔术,对照组开腹后不做任何处理,均尾静脉输注相同容量的生理盐水。24 h后麻醉处死实验动物,取心肌标本,采用苏木精-伊红染色观察心肌组织形态;用Western blot方法检测心肌组织中凋亡蛋白Bax、Caspase-3,抗凋亡蛋白Bcl-2的表达量。结果与结论:苏木精-伊红染色结果:对照组可见心肌细胞排列整齐,心肌细胞结构完整;模型组可见广泛心肌纤维断裂,排列紊乱,心肌细胞肿胀或皱缩,可见空泡变性;心肌间质血管充血、水肿,炎症细胞浸润;促红细胞生成素组与骨髓间充质干细胞组心肌组织相似,炎性细胞浸润情况较轻,期间散在分布正常心肌细胞;促红细胞生成素+细胞移植组心肌细胞损害较轻,间质充血不明显,少量炎症细胞浸润。Western blot结果:促红细胞生成素+细胞移植组Bcl-2蛋白表达显著高于促红细胞生成素组、模型组及对照组(P<0.01),Bax及Caspase-3蛋白表达量均减低(P<0.05)。结果显示,骨髓间充质干细胞移植联合给予促红细胞生成素在脓毒症相关性心肌损伤的治疗中可减轻心肌的病理学改变、抑制心肌细胞的凋亡,其机制可能是通过上调抗凋亡蛋白、下调凋亡蛋白的表达来实现的。

BACKGROUND：Erythropoietin and bone marrow mesenchymal stem cells have been shown to affect myocardial apoptosis. However, few studies concerned their combined application to sepsis-related myocardial injury. OBJECTIVE：To observe the effects of the combination of erythropoietin and bone marrow mesenchymal stem cells on pathology and apoptosis of sepsis rat cardiomyocytes. METHODS：A total of 50 Sprague-Dawley rats were randomly selected and assigned to five groups （n=10）. Sepsis models were established by cecal ligation perforation method. Rat models in the bone marrow mesenchymal stem cellgroup, erythropoietin group and erythropoietin＋bone marrow mesenchymal stem cellgroup were respectively treated with bone marrow mesenchymal stem cells, erythropoietin and erythropoietin＋bone marrow mesenchymal stem cells immediately after model induction via intraperitoneal injection or caudal vein. Model group received cecum ligation and puncture. Control group did not undergo any treatment after the abdomen was opened. Model and control groups were infused with an equal volume of physiological saline via caudal vein. At 24 hours, experimental animals were sacrificed by anesthesia. Myocardial specimens were col ected. Myocardial appearance was observed using hematoxylin-eosin staining. Bax, Caspase-3 and Bcl-2 were tested by western blot assay. RESULTS AND CONCLUSION：Hematoxylin-eosin staining：cardiomyocytes were regularly arranged, showing integrated structure in the control group. Extensive myocardial fiber breakage, disordered arrangement, cardiomyocyte swel ing or shrinkage, and vacuolar degeneration were observed in the model group. Moreover, myocardial interstitial vascular congestion, edema, and inflammatory cellinfiltration were visible. Myocardial tissue was similar between erythropoietin and bone marrow mesenchymal stem cellgroups, with the presence of mild inflammatory cellinfiltration and scattered normal cardiomyocytes. In the erythropoietin＋bone marrow mesenchymal stem cellgroup, cardiomyocytes were slightly damaged. Interstitial vascular congestion was not apparent, and a few inflammatory cells infiltrated. Western blot assay results demonstrated that Bcl-2 protein expression was significantly higher （P〈0.01）, but Bax and Caspase-3 protein expression was lower （P〈0.05） in the erythropoietin＋bone marrow mesenchymal stem cellgroup than in the erythropoietin, model and control groups. The combination of erythropoietin and bone marrow mesenchymal stem cells in treatment of sepsis-related myocardial injury could lessen myocardial pathological changes, and inhibit cardiomyocyte apoptosis. The mechanisms maybe exert by upregulating anti-apoptotic protein expression and downregulating apoptotic protein expression.