The molecular effect of general anesthesia on alveolar macrophages

人类研究：我们研究了在大型骨科手术中用异丙酚或异氟醚麻醉的患者。分别于麻醉诱导后即刻、麻醉诱导后2、4、6h及手术结束时经支气管肺泡灌洗取肺泡巨噬细胞。测定聚集和死亡巨噬细胞的比例。然后，我们通过摄取调理和未调理的颗粒来测量吞噬功能。随着时间的推移，肺泡巨噬细胞吞噬调理颗粒和非调理颗粒的比例和吞噬颗粒的数量显著减少，异氟醚麻醉期间，这种下降幅度略大，但明显更大。在麻醉和手术过程中，杀菌功能逐渐下降，异氟醚的降幅几乎是异丙酚麻醉时的两倍。在给予每种麻醉剂的患者中，聚集的巨噬细胞和恢复的中性粒细胞的比例随着时间的推移而增加。ANIMAL研究：大鼠接受了气管切开和机械通气。分别于无吸入麻醉剂机械通气2小时、1-MAC异氟醚机械通气2小时、1-MAC氟烷机械通气2小时后，行肺泡灌洗取肺泡巨噬细胞。提取RNA，用逆转录酶合成c DNA。4种细胞因子：IL-1α和β、IL-6、干扰素和肿瘤坏死因子-α以及巨噬细胞炎性蛋白-2(MIP-2)分别用3‘和5’-特异性引物扩增。在实验前，我们建立了导致指数扩增的聚合酶链式反应条件。对于所有细胞因子，在没有麻醉剂的情况下，两小时的机械通气后，所有细胞因子的基因表达都是最低的。异氟醚机械通气后2小时可见IL-1、干扰素、肿瘤坏死因子基因表达。

HUMAN STUDY : We studied patients anesthetized with propofol (n=30) or isoflurane (n=30) during major orthopedic surgery. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, and 2,4, and 6 hours after induction anesthesia and at the end of surgery. The fraction of aggregated and nonviable macrophages was determined. We then measured phagocytosis by ingestion of opsonized and unopsonized particles. Finally, microbicidal activity was determined as the ability of the macrophages to directly kill Listeria monocytogenes.The fraction of alveolar macrophages ingesting opsonized and non-opsonized particles, and the number of particles ingested, decreased significantly over time, with the decrease being slightly but significantly greater during isoflurane anesthesia. Microbicidal function progressively decreased during anesthesia and surgery, with the decrease being almost twice as great during isoflurane than propofol anesthesia. The fraction of aggregated macrophages and recovered neutrophils increased over time in the patients given each anesthetic.ANIMAL STUDY : Rats received a tracheostomy followed by mechanical ventilation. We performed bronchoalveolar lavage to harvest AMs at the following time points : after two-hour mechanical ventilation without inhaled anesthetics, after two-hour mechanical ventilation with 1-MAC isoflurane, and after two-hour mechanical ventilation with 1-MAC halothane. We extracted RNAs and cDNA was synthesized with reverse transcriptase. We used specific 3'- and 5'-primers for four cytokines : IL-1alpha and beta, IL-6, IFN and TNF-alpha and macrophage inflammatory protein-2 (MIP-2). Before the experiment, we established the PCR condition that resulted in exponential amplification. For all cytokines, gene expression of all cytokines was minimal after two-hour mechanical ventilation without anesthetics. We found gene expression of IL-1, IFN,and TNF two hours after mechanical ventilation with isoflurane.