内皮细胞在不同间歇缺氧方式时核因子κB和细胞间黏附分子1的变化

目的测定人脐静脉内皮细胞可传代细胞株ECV304在不同间歇缺氧（IH）程度、频率、时段和恢复时段下核因子κB（NF-κB）和细胞间黏附分子1（ICAM-1）的变化。方法在自制细胞培养舱中程控产生预置的IH／ROX（再氧合）暴露环境，将ECV304细胞暴露于该环境共60次循环。暴露时按IH／ROX时段将细胞分为11组，每组样本数为12。A组：采用21％O215s／21％O2 3分钟45秒（即间歇正常氧）方案；B组：置于标准孵箱中不加暴露（标准孵育）；C组：采用1．5％O2 15s／21％O2 3分钟45秒方案；D组：采用10％O2 15s／21％O2 3分钟45秒方案；以下固定IH方案为1．5％O2 15s和ROX程度21％O2不变，IH／ROX循环频率分别为12S／h（C组）、9S／h（E组）、6S／h（F组）、20S／h（G组）和40S／h（H组）；I组：采用1．5％O2 30s／21％O23分钟45秒方案；C组完成暴露后放回标准孵箱中60min为J组，120min为K组。分别采用酶联免疫吸附（ELISA）法和细胞表面ELISA法测定细胞裂解液中总NF-κB水平和细胞表面ICAM-1浓度，并测定总蛋白含量。结果C组NF-κB和ICAM-1水平分别为（0．82±0．28）、（1562±56）pg／ml，A组分别为（0．37±0.07）、（768±80）pg／ml，两组比较差异有统计学意义（D值分别为225．00、176．04，P分别〈0．01、〈0．05）；D组分别为（0．66±0．22）、（1113±76）pg／ml，与C组比较差异有统计学意义（U值分别为25．00、0．00，P均〈0.01）；I组分别为（0．45±0.16）、（1155±19）pg／ml，与C组比较差异有统计学意义（U值分别为27．00、0．00，P均〈0.01）；同时C组的NF-κB和ICAM-1水平在C、E、F、G和H这5个不同IH频率组的比较亦是相对最高的（X^2分别为35．63、56．89，P均〈0.01）；J组NF-κB水平[（0．6233±0.0534）]与C组比较差异无统计学意义（D=36．00，P〉0．05），而K组NF-κB水平[（0．3050±0．0013）]与C组比较差异有统计学意义（D=234．00，P〈0．01）。结论IH／ROX可对内皮细胞造成程度依赖的炎性损伤且不易恢复，中度频率的IH／ROX将选择性激活细胞炎性通道。而过高频率和过长时段的IH反而激活细胞适应性通道。

Changes of nuclear factor-κB and intercellular adhesion molecule-1 in endothelial cells exposed to various intermittent hypoxia

OBJECTIVE: To construct a novel in vitro endothelial cell system to explore the changes of nuclear factor-kappaB (NF-kappaB) and intercellular adhesion molecule-1 (ICAM-1) levels after exposure to various intermittent hypoxia (IH) and re-oxygenation, an IH/reoxygenation (ROX) model. METHODS: We developed a gas control delivery system that permited the exposure of ECV304 cell cultures, immortalized endothelial cell strain cultures of human umbilical vein endothelial cells (HUVEC), to IH/ROX cycles, simulating the pattern of hypoxic episodes seen in recurrent apnea. Cell samples were divided into the following groups according to IH duration/ROX duration. Group A (Intermittent Normoxia Group): 21% O(2) 15 s/21% O(2) 3 min 45 s; Group B (Standard Culture Group): no exposure; Group C: 1.5% O(2) 15 s/21% O(2) 3 min 45 s; Group D: 10% O(2) 15 s/21% O(2) 3 min 45 s; Fixed IH protocol as 1.5% O(2) 15s and ROX extent to 21% O(2), IH/ROX frequencies varied as 12 (Group C), 9.23 (Group E), 6.32 (Group F), 20 (Group G) and 40 (Group H) episodes per hour; Group I: 1.5% O(2) 30 s/21% O(2) 3 min 45 s; and after the exposure of Group C, the cell cultures were exposed to standard incubation device for 60 min (Group J) and 120 min (Group K). Prepared cell lysates and cell monolayers were analyzed for NF-kappaB levels and ICAM-1 levels in this IH model with enzyme-linked immunosorbent assay (ELISA) and cellular surface ELISA, and the cell total protein levels were measured with the method of bicinchoninic acid for standardization. SPSS 11.5 software package was used for statistical analysis. RESULTS: NF-kappaB and ICAM-1 levels in Group C were (0.82 +/- 0.28) and (1562 +/- 56) pg/ml, and those in Group A were (0.37 +/- 0.07) and (768 +/- 80) pg/ml, which showed statistical significance as compared with Group C (D = 225.00, 176.04, P < 0.01, < 0.05, respectively). Their levels in Group D were (0.66 +/- 0.22) and (1113 +/- 76) pg/ml, which were also significantly lower than Group C (U = 25.00, 0.00, all P < 0.01). NF-kappaB and ICAM-1 levels in Group I were (0.45 +/- 0.16) and (1155 +/- 19) pg/ml, which were statistically significant compared with Group C (U = 27.00, 0.00, all P < 0.01). In the same time, IH group had the relatively highest NF-kappaB and ICAM-1 levels amongst groups C, E, F, G and H. Which had different IH frequencies (chi(2) = 35.63, 56.89, all P < 0.01). NF-kappaB levels in Group J [(0.6233 +/- 0.0534)] did not differ significantly from Group C (D = 36.00, P > 0.05) and NF-kappaB levels in Group K [(0.3050 +/- 0.0013)] were lower than Group C (D = 234.00, P < 0.01). CONCLUSIONS: Our data indicated a selective and dose-dependent activation of inflammatory pathways on ECV304 cells by IH/ROX cycles with moderate frequencies, and a long time was needed for the cell rehabilitation from IH/ROX exposure.