内皮细胞类表皮生长因子域7对血管平滑肌细胞凋亡的影响

目的 探讨人脐静脉内皮细胞株（HUVEC）中类表皮生长因子功能域7（EGFL7）对共培养的人主动脉平滑肌细胞（AoSMC）凋亡的影响以及可能的信号转导通路。方法 利用细胞共培养池行HUVEC与AoSMC共培养，将EGFL7的特异siRNA转染HUVEC细胞，利用MTS法检测HUVEC中EGFL7基因的有效沉默对共培养的AoSMC细胞存活率的影响；并合成无关siRNA作为阴性对照组（neg组），以未转染siRNA的细胞为空白对照组（con组）。同时利用分光光度法检测其对AoSMC细胞乳酸脱氢酶（LDH）、三磷酸腺苷（ATP）以及细胞凋亡蛋白酶（Caspase-3 ）表达的影响；应用RT-PCR检测共培养AoSMC 的bcl-2及bax mRNA表达水平的改变。结果 与neg组及con组相比，干扰HUVEC细胞EGFL7表达12h后，AoSMC存活率无明显变化（P>0.05），而干扰24、36、48h后，存活率显著降低（P<0.05）；干扰12、24、36、48h后，AoSMC细胞线粒体ATP释放量减少、培养基中LDH含量及Caspase-3表达量均增加（P<0.05）。RT-PCR检测结果显示，与neg组及con组相比，干扰siRNA转染HUVEC细胞24、36、48h，共培养的AoSMC凋亡基因bcl 2表达水平轻度降低（P<0.05）；但Bax表达水平在相应干预时间点均无明显改变（P>0.05）。结论 内皮细胞株EGFL7基因沉默时，可导致平滑肌细胞凋亡；EGFL7通过bcl-2相关信号通路调节SMC凋亡，而与Bax基因表达无关。

Epidermal growth factor-like domain 7 regulating apoptosis of human aortic smooth muscle cells

Objective   To investigate the effect of epidermal growth factor (EGF)-like domain 7 (EGFL7) of human umbilical vein endothelial cells (HUVEC) on apoptosis of co cultured human aortic smooth muscle cells (AoSMC) and its signal transduction pathway. Methods   HUVEC and AoSMC were co-cultured in cell co-culture pools. The special siRNA targeting EGFL7 was transfected into HUVEC by lipofectamine, irrelevant siRNA as the negative group(neg) and siRNA-nontransfected cells as the control group(con).When the Egfl7 gene was silenced in HUVEC, AoSMC cell survival rates were determined by MTS, LDH, ATP and Caspase-3 release amount by spectrophotometry, and Bcl-2 and bax expressions in AoSMC by RT-PCR. Results   AoSMC survival rates decreased significantly after 24,36 and 48 hours（P<0.05）. There were significant differences in ATP release amount, LDH content in medium and Caspase-3amount at 12, 24, 36 and 48 hours（P<0.05）. The bcl-2 expression was gently reduced and there were significant differences at 24, 36 and 48 hours compared with the control and negative group（P<0.05）. While there was no significant difference in the bax expression（P>0.05）. Conclusion   The silence of EGFL7 in HUVEC could promote apoptosis of AoSMC. EGFL7 may regulate apoptosis of SMC via Bcl-2-related signal pathway.