基质金属蛋白酶9在糖尿病视网膜病变发展中的凋亡作用

Apoptotic Effect of Matrix Metalloproteinases 9 in the Development of Diabetic Retinopathy

目的为了探索基质金属蛋白酶9(MMP9)在糖尿病视网膜病变(DR)进展中的潜在调节机制。方法利用Lipofectamine 2000将pc DNA-MMP9质粒和pc DNA-Ang2质粒分别转染至原代大鼠视网膜Müller细胞(RMCs)中。分别利用MTT法与流式细胞仪检测细胞生存率与凋亡情况。同时探索了MMP9与血管紧张素2(Ang2)之间的交互作用。另外,RMCs分别在正常血糖水平与高血糖水平下用MMP9处理2天。此外,通过Western印迹测定细胞凋亡蛋白MMP9、Ang2、Bax2、Bcl2、聚腺苷二磷酸核糖聚合酶(PARP)降解产物、天门冬氨酸特异性半胱氨酸蛋白酶-3(caspase3)降解产物的表达水平。结果与对照组相比,siRNA-MMP9组细胞生存率显著增长而MMP9过表达组下降。与对照组相比,MMP9过表达组中细胞凋亡显著增加,而si RNA-MMP9组中则下降。MMP9表达由Ang2显着调节,而当MMP9表达改变时,Ang2表达无明显变化。再者,高血糖组中MMP9的表达显著性增加,而正常血糖组与对照组比较差异无统计学意义。另外,高血糖组中Bax2,Bcl2,PARP降解产物、caspase3降解产物的表达也显著增加,相应地对照组与正常血糖组则没有显著性改变。结论我们的研究结果表明,MMP9通过由Ang2调控或定位细胞凋亡相关蛋白(如Bax2,Bcl2,PARP降解产物、caspase3降解产物)诱导细胞凋亡,在DR进展中扮演着一个重要角色。

Objective To explore the potential regulatory mechanism of MMP9 in the development of DR. Methods Plasmids pc DNA-MMP9 and pc DNA-Ang2 were transfected into primary rat retinal Müller cells（RMCs） using Lipofectamine 2000. Cell viability and apoptosis were respectively determined by MTT assay and flow cytometry. Moreover, the interaction between MMP9 and Ang2 was explored. Besides, RMCs were treated with MMP-9 under normal glucose and high glucose（HG） condition for 2 d. Besides, the expression levels of apoptotic proteins, like MMP9, Ang2, Bax2, Bcl2, cleaved PARP and cleaved caspase3 were determined by Western blot. Results The cell viability of siRNA-MMP9 group was significantly increased while decreased in MMP9 overexpression group when compared to control group, respectively. The apoptotic cells in MMP9 overexpression group significantly increased while decreased in si RNA-MMP9 group when compared with control group. MMP9 expression was significantly regulated by Ang2 whereas no significant changes occurred in Ang2 expression when MMP9 expression changed. Moreover, MMP9 expression in HG group significantly increased while there were no significant differences between NG group and control group. Besides, the expression of Bax2, Bcl2, cleaved PARP and cleaved caspase3 in HG group increased while there were no significant differences between NG group and control group. Conclusion Our findings indicate that MMP9 may play an important role via inducing cell apoptosis in the development of DR via regulating by Ang2 or targeting apoptotic proteins, such as Bax2, Bcl2, cleaved PARP and cleaved caspase3.