Zuckerberg A L, Goldberg L I, Lederman H M
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
Crit Care Med. 1994 Feb;22(2):197-203. doi: 10.1097/00003246-199402000-00008.
To investigate the effects of hypoxia on T-lymphocyte expression of IL-2 messenger RNA (mRNA), after cell activation with phorbol ester and ionomycin.
Prospective, controlled, cellular trial.
University research laboratory.
EL4.6.1 cells, a murine T-cell lymphoma line.
Tissue culture media was deoxygenated and flushed continuously with 100% helium to maintain a PO2 of 30 to 40 torr (< 40 torr [< 5.3 kPa]), or flushed with 10% oxygen/90% helium to maintain a PO2 of 45 to 55 torr (> 45 torr [> 6.0 kPa]). The pH was maintained between 7.3 and 7.6. The media was inoculated with EL4 cells. Aliquots of cells were obtained at intervals and divided into two groups: an immediate group, stimulated immediately, and an overnight group that was returned to normal incubator conditions of 5% CO2/humidified room air for 18 hrs before stimulation.
Gas tension, pH, cell count, and viability were determined for each aliquot. Cells were stimulated with phorbol myristate acetate and ionomycin for 4 hrs, at which time levels of interleukin-2 (IL-2) messenger RNA (mRNA) and gamma actin mRNA were measured by solution hybridization and enzyme immunoassay. The results were expressed as IL-2 mRNA/gamma actin mRNA ratio, normalised to baseline room air values. Cell viability and housekeeping functions (gamma actin mRNA expression) were unaffected by hypoxia. Cells exposed to a PO2 of < 40 torr (< 5.3 kPa) demonstrated a dramatic reduction in IL-2 mRNA expression with increasing duration of hypoxia. These effects persisted after an 18-hr recovery period. There was no effect on IL-2 mRNA expression when cells were exposed to a PO2 of > 45 torr (> 6.0 kPa).
The regulation of IL-2 transcription in the T lymphocyte appears to be exquisitely sensitive to changes in oxygen tension. Exposure to a PO2 of < 40 torr (< 5.3 kPa) causes prolonged impairment of IL-2 mRNA expression. IL-2 is an important growth factor for T and NK cells, and plays a pivotal role in the regulation of the host's immune response. The long-lasting effects of brief hypoxic exposure may, in part, explain the critically ill patient's predisposition to infectious complications.
研究在用佛波酯和离子霉素激活细胞后，缺氧对T淋巴细胞白细胞介素-2信使核糖核酸（mRNA）表达的影响。
前瞻性、对照性细胞试验。
大学研究实验室。
EL4.6.1细胞，一种小鼠T细胞淋巴瘤细胞系。
将组织培养基脱氧，并用100%氦气持续冲洗以维持30至40托（<40托[<5.3千帕]）的氧分压，或用10%氧气/90%氦气冲洗以维持45至55托（>45托[>6.0千帕]）的氧分压。pH维持在7.3至7.6之间。将培养基接种EL4细胞。每隔一段时间获取细胞 aliquots，并分为两组：立即刺激组，立即进行刺激；过夜组，在刺激前返回5%二氧化碳/湿润室内空气的正常培养箱条件下培养18小时。
测定每个 aliquots 的气体张力、pH、细胞计数和活力。用佛波醇肉豆蔻酸酯和离子霉素刺激细胞4小时，此时通过溶液杂交和酶免疫测定法测量白细胞介素-2（IL-2）信使核糖核酸（mRNA）和γ肌动蛋白mRNA的水平。结果以IL-2 mRNA/γ肌动蛋白mRNA比值表示，并根据基线室内空气值进行标准化。细胞活力和管家功能（γ肌动蛋白mRNA表达）不受缺氧影响。暴露于氧分压<40托（<5.3千帕）的细胞，随着缺氧时间延长，IL-2 mRNA表达显著降低。这些影响在18小时的恢复期后仍然存在。当细胞暴露于氧分压>45托（>6.0千帕）时，对IL-2 mRNA表达没有影响。
T淋巴细胞中IL-2转录的调节似乎对氧张力变化极为敏感。暴露于氧分压<40托（<5.3千帕）会导致IL-2 mRNA表达长期受损。IL-2是T细胞和NK细胞的重要生长因子，在宿主免疫反应调节中起关键作用。短暂缺氧暴露的长期影响可能部分解释了重症患者易发生感染并发症的原因。
