骨髓细胞移植上调急性缺血心肌HSP32和HSP70的表达

目的 :检测骨髓细胞移植在急性心肌梗死大鼠模型中对细胞保护性蛋白HSP32和HSP70表达水平的影响 ,探讨细胞移植早期改善缺血心脏功能的可能机制。方法 :通过结扎冠状动脉左前降支制备大鼠心肌梗死模型 ,直视下心外膜注射 5× 10 6骨髓单个核细胞 ;利用免疫荧光和RT -PCR技术检测HSP32和HSP70在术后 1d、3d、7d和 14d的表达变化和移植细胞的分化情况 ;通过超声心动图分析心脏功能左室射血分数 (EF值 )和缩短分数(FS值 )。结果 :免疫荧光结果显示 ,缺血心肌中HSP32和HSP70的表达在移植组明显增强 ,并表达于部分移植细胞内。RT -PCR结果表明 ,移植组HSP32和HSP70的mRNA表达明显高于对照组 ,术后 3d达到高峰 ,比对照组分别增加 5 .0倍和 2 .9倍 (P <0 .0 1)。术后 7d ,移植组EF值和FS值明显高于同期对照组 (14 %和 2 2 % ,P <0 .0 5 ) ;术后 14d ,可在移植的骨髓细胞中检测到心肌细胞和血管内皮细胞特异性蛋白的表达 ,EF值和FS值进一步增加。结论 :骨髓细胞移植早期 ,细胞移植能够上调细胞保护性蛋白的表达 ,促进急性缺血心脏功能恢复

Transplantation of bone marrow cells up-regulated the expressions of HSP32 and HSP70 in the acute ischemic myocardium

OBJECTIVE: To clarify the role of Heat shock proteins (HSPs) on the cardiac function during acute myocardial infarction (AMI) after bone marrow cell implantation (BMT), we examined the expression of HSP32 and HSP70 in a rat model of myocardial infarction. METHODS: Myocardial infarction model was induced in the inbred Lewis rats by left anterior descending artery ligation, and 5 x 10(6) of bone marrow-mononuclear cells (BM-MNCs) were injected into an ischemic zone. On days 1, 3, 7 and 14 post-infarct, the differentiations of transplanted cells and the expressions of HSP32 and HSP70 were determined by immunofluorescence or RT-PCR. The cardiac function was evaluated by echocardiography. RESULTS: Immunofluorescence microscopy of hearts from BMT group revealed that expressions of HSP32 and HSP70 were promoted within cardiomyocytes in the infarction zone and the peri-infarct zone, and expressed within some transplanted bone marrow cells as well. RT-PCR also showed the mRNA expression levels of HSP32 and HSP70 in BMT group were significantly higher than those of the control group, peaked on day 3 post-infarct (5.0-fold and 2.9-fold, respectively, P < 0.01), and then gradually reduced. On day 7 post-infarct, cardiac function (EF and FS) was improved, more than that of the control group (14% and 22%, P < 0.05). On day 14 post-infarct, the specific markers for myocardium or vascular endothelial cells were detected in the transplanted bone marrow cells. The cardiac function was further improved in the BMT group (P < 0.01). CONCLUSION: At the early phase after BMT, the expressions of HSP32 and HSP70 were upregulated in both transplanted cells and recipient endogenous cardiomyocytes, which improved the acute ischemic cardiac function.