Department of Hepatobiliary Surgery, Air Force Medical Center, PLA, Beijing 100142, China.
Department of Pediatrics, Chinese PLA General Hospital and PLA Medical School, Beijing 100853, China.
World J Gastroenterol. 2019 Jan 21;25(3):346-355. doi: 10.3748/wjg.v25.i3.346.
Exposure to high sustained +Gz (head-to-foot inertial load) is known to have harmful effects on pilots' body in flight. Although clinical data have shown that liver dysfunction occurs in pilots, the precise cause has not been well defined.
To investigate rat liver function changes in response to repeated +Gz exposure.
Ninety male Wistar rats were randomly divided into a blank control group (BC group, = 30), a +6 Gz/5 min stress group (6GS group, = 30), and a +10 Gz/5min stress group (10GS group, = 30). The 6GS and 10GS groups were exposed to +6 Gz and +10 Gz, respectively, in an animal centrifuge. The onset rate of +Gz was 0.5 G/s. The sustained time at peak +Gz was 5 min for each exposure (for 5 exposures, and 5-min intervals between exposures for a total exposure and non-exposure time of 50 min). We assessed liver injury by measuring the portal venous flow volume, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), liver tissue malondialdehyde (MDA), Na-K-ATPase, and changes in liver histology. These parameters were recorded at 0 h, 6 h, and 24 h after repeated +Gz exposures.
After repeated +Gz exposures in the 6GS and the 10GS groups, the velocity and flow signal in the portal vein (PV) were significantly decreased as compared to the BC group at 0 h after exposure. Meanwhile, we found that the PV diameter did not change significantly. However, rats in the 6GS group had a much higher portal venous flow volume than the 10GS group at 0 h after exposure. The 6GS group had significantly lower ALT, AST, and MDA values than the 10GS group 0 h and 6 h post exposure. The Na-K-ATPase activity in the 6GS group was significantly higher than that in the 10GS group 0 h and 6 h post exposure. Hepatocyte injury, determined pathologically, was significantly lower in the 6GS group than in the 10GS group.
Repeated +Gz exposures transiently cause hepatocyte injury and affect liver metabolism and morphological structure.
已知暴露于高持续的+Gz（从头至脚的惯性负荷）对飞行员在飞行中的身体有有害影响。尽管临床数据表明飞行员会出现肝功能障碍，但确切原因尚未明确。
研究大鼠肝脏功能对重复+Gz 暴露的反应变化。
将 90 只雄性 Wistar 大鼠随机分为空白对照组（BC 组，n=30）、+6 Gz/5 分钟应激组（6GS 组，n=30）和+10 Gz/5 分钟应激组（10GS 组，n=30）。6GS 和 10GS 组分别在动物离心机中暴露于+6 Gz 和+10 Gz。+Gz 的起始速度为 0.5 G/s。每个暴露的峰值+Gz 持续时间为 5 分钟（共 5 次暴露，每次暴露之间间隔 5 分钟，总暴露和非暴露时间为 50 分钟）。我们通过测量门静脉血流量、血清丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AST）、肝组织丙二醛（MDA）、Na-K-ATP 酶以及肝组织学变化来评估肝损伤。这些参数在重复+Gz 暴露后 0 h、6 h 和 24 h 记录。
在 6GS 和 10GS 组重复+Gz 暴露后，与 BC 组相比，暴露后 0 h 时门静脉（PV）的速度和血流信号明显降低。同时，我们发现 PV 直径没有明显变化。然而，暴露后 0 h 时，6GS 组的门静脉血流量明显高于 10GS 组。6GS 组在暴露后 0 h 和 6 h 的 ALT、AST 和 MDA 值明显低于 10GS 组。6GS 组在暴露后 0 h 和 6 h 的 Na-K-ATP 酶活性明显高于 10GS 组。病理确定的肝细胞损伤在 6GS 组明显低于 10GS 组。
重复+Gz 暴露会导致短暂的肝细胞损伤，并影响肝脏代谢和形态结构。
