间歇低氧状态下大鼠血管损伤及损伤后修复的机制探讨

摘要

目的：探讨间歇低氧（ IH）状态下大鼠血管损伤及损伤后修复的机制。方法将30只雄性Wistar大鼠随机分为正常氧对照组（ IN组）和IH组各15只，两组在第13～16周分别予正常氧、IH处理。第16周末收集大鼠静脉血，Elisa法测定血浆TNF-α、IL-6，流式细胞计数仪计数外周血内皮祖细胞（EPC）。取颈动脉组织，石蜡包埋、切片、HE染色，光镜观察，使用Photoshop软件测量各个点在图形中的像素位置来计算颈总动脉的内中膜厚度占全层厚度的比例（ C-IMT％）；采用Elisa法测定颈动脉内皮组织中TNF-α、IL-6，采用Real-time-PCR法检测颈动脉内皮细胞中RhoA mRNA。结果 IH组与IN组C-IMT％分别为（0．534±0．02）、（0．488±0．013），IH组血管弹性下降，硬度增加，血管发生炎性损伤。 IH组与IN组血浆TNF-α分别为（48．59±3．20）、（16．47±2．25） pg/mL，IL-6分别为（264．57±16．69）、（109．71±7．84）pg/mL，颈动脉内皮细胞中TNF-α分别为（112．90±13．91）、（37．60±3．98） pg/mL，IL-6分别为（675．30±15．01）、（434．60±16．05）pg/mL，两组比较，P均＜0．05。 IH组与IN组血EPC分别为（5．85±0．43）、（8．89±0．59）个/μL，颈动脉内皮细胞中RhoA mRNA相对表达量分别为（1．56±0．05）、（1．00±0．00），两组比较，P均＜0．05。结论 IH状态下大鼠血管发生炎性损伤，其机制可能为IH激活RhoA通路，使内皮细胞通透性增加，系统性炎症反应增强；同时IH状态下外周血EPC数量降低，归巢至血管损伤部位的EPC减少，血管内皮修复能力降低。%Objective To explore the mechanism of vascular endothelial injury and repair in an intermittent hypoxia (IH) rat model.Methods 30 male Wistar rats were randomly divided to two groups according to the exposure conditions :(1) normal oxygen control group (IN group, n=15);(2) IH group (n=15).In 13~16 weeks, two groups were ex-posed to normal oxygen or IH, respectively.After exposure, ELISA method was used to detect value of tumor necrosis fac-tor alpha ( TNF-α) and interleukin ( IL)-6 in plasma and in the endothelium of right common carotid artery .Real-time-PCR assay was used to analyze RhoA mRNA level in the endothelium of right carotid artery .Flow cytometry was used to de-tect EPC level in peripheral blood .We also obtained a piece of tissue of right carotid artery , then performed paraffin em-bedding, sectioning, HE staining, and observed in light microscope for counting the percentage of intima-media thickness (IMT) in the all wall (C-IMT%) by means of Photoshop software .Results IH group had higher TNF-α(48.59 ±3.20 vs 16.47 ±2.25 pg/mL in plasma;112.90 ±13.91 vs 37.60 ±3.98 pg/mL in endothelial cell), IL-6 (264.57 ±16.69 vs 109.71 ±7.84 pg/mL in plasma;675.30 ±15.01 vs 434.60 ±16.05pg/mL in endothelial cell), RhoA mRNA (1.56 ± 0.05 vs 1.00 ±0.00) and C-IMT%(0.534 ±0.02 vs 0.488 ±0.013) than IN group (all P<0.05).The elasticity of vessel decreased , and hardness increased in IH group , that occurred inflammatory injury .The quantity of endothelial pro-genitor cell (EPC) were higher in IN group than IH group (8.89 ±0.59 vs 5.85 ±0.43个/μL, P<0.05).Conclusion IH damaged vascular endothelium in rat , activated the inflammation pathway of TNF-α, IL-6 and RhoA , increased endo-thelial cell premeability and systematic inflammation .At the same time, IH reduced the quantity of EPC both in peripheral blood and in the damage region , as a result the repair capacity for endothelium reduced , which increased the risk of cardio-vascular diseases .