Department of Hepatobiliary-pancreatic and Transplant Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Department of Biology, University of North Florida, Jacksonville, Florida.
J Surg Res. 2019 Apr;236:172-183. doi: 10.1016/j.jss.2018.11.047. Epub 2018 Dec 17.
Acute liver failure (ALF) from severe acute liver injury is a critical condition associated with high mortality. The purpose of this study was to investigate the impact of preemptive administration of γ-aminobutyric acid (GABA) on hepatic injury and survival outcomes in mice with experimentally induced ALF.
To induce ALF, C57BL/6NHsd mice were administered GABA, saline, or nothing for 7 d, followed by intraperitoneal administration of 500 μg of tumor necrosis factor α and 20 mg of D-galactosamine. The study mice were humanely euthanized 4-5 h after ALF was induced or observed for survival. Proteins present in the blood samples and liver tissue from the euthanized mice were analyzed using Western blot and immunohistochemical and histopathologic analyses. For inhibition studies, we administered the STAT3-specific inhibitor, NSC74859, 90 min before ALF induction.
We found that GABA-treated mice had substantial attenuation of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive hepatocytes and hepatocellular necrosis, decreased caspase-3, H2AX, and p38 MAPK protein levels and increased expressions of Jak2, STAT3, Bcl-2, and Mn-SOD, with improved mitochondrial integrity. The reduced apoptotic proteins led to a significantly prolonged survival after ALF induction in GABA-treated mice. The STAT3-specific inhibitor NSC74859 eliminated the survival advantage in GABA-treated mice with ALF, indicating the involvement of the STAT3 pathway in GABA-induced reduction in apoptosis.
Our results showed that preemptive treatment with GABA protected against severe acute liver injury in mice via GABA-mediated STAT3 signaling. Preemptive administration of GABA may be a useful approach to optimize marginal donor livers before transplantation.
严重急性肝损伤导致的急性肝衰竭（ALF）是一种高死亡率的危急情况。本研究旨在探讨预先给予γ-氨基丁酸（GABA）对实验诱导的 ALF 小鼠肝损伤和生存结果的影响。
为诱导 ALF，C57BL/6NHsd 小鼠给予 GABA、生理盐水或不给予 GABA 预处理 7d，然后腹腔内给予 500μg 肿瘤坏死因子-α和 20mg D-半乳糖胺。诱导 ALF 后 4-5h 对研究小鼠进行安乐死，或观察其生存情况。通过 Western blot、免疫组化和组织病理学分析，分析安乐死小鼠血液样本和肝组织中的蛋白质。为了进行抑制研究，我们在诱导 ALF 前 90min 给予 STAT3 特异性抑制剂 NSC74859。
我们发现，GABA 处理的小鼠的末端脱氧核苷酸转移酶 dUTP 缺口末端标记阳性肝细胞和肝细胞坏死明显减少，caspase-3、H2AX 和 p38 MAPK 蛋白水平降低，Jak2、STAT3、Bcl-2 和 Mn-SOD 表达增加，线粒体完整性得到改善。凋亡蛋白减少导致 GABA 处理的 ALF 小鼠诱导后生存时间显著延长。STAT3 特异性抑制剂 NSC74859 消除了 GABA 处理的 ALF 小鼠的生存优势，表明 STAT3 途径参与了 GABA 诱导的凋亡减少。
我们的结果表明，预先给予 GABA 通过 GABA 介导的 STAT3 信号通路保护小鼠免受严重急性肝损伤。预先给予 GABA 可能是在移植前优化边缘供体肝脏的一种有用方法。
