Hepatic encephalopathy (HE) is a devastating neuropsychiatric presentation of the advanced hepatic insufficiency. It is associated with high morbidity and mortality. Aquaporin-4 (AQP4), the principal astrocyte water channel, is primarily involved in brain edema development. Ulinastatin (ULI) is a potent protease inhibitor, extracted from fresh human urine. We hypothesized that ULI could be neuroprotective in acute HE through molecular targeting of brain AQP4, which is known to be upregulated in HE. To induce acute liver failure (ALF), the rats were acutely intoxicated with thioacetamide (TAA). Animals were randomized into HE- and ULI-treated HE groups, with control normal group. Total bilirubin, albumin, serum aminotransferases, and serum/brain ammonia/proinflammatory cytokines, blood–brain barrier (BBB) integrity/tight junction proteins, brain water content, and neurological scores were assessed. Additionally, brain AQP4 and α-Syntrophin mRNA expression and protein levels were evaluated by quantitative real-time PCR and enzyme-linked immunosorbent assay, respectively. Brain and liver tissues were stripped and processed for further microscopic and histological analyses. ULI exerted potent dual neuro/hepato protective potential, improved neurological score, animals’ survival, ameliorated brain edema, probably via anti-inflammatory activity, preserved BBB integrity, down-regulated AQP4 expression, and membrane polarization by decreased α-syntrophin level, with rescued brain bioenergetics. ULI could be tooled as a possible therapeutic option in HE in ALF.

Graphical abstract

肝性脑病（HE）是晚期肝功能不全的毁灭性神经精神病学表现。它与高发病率和高死亡率有关。Aquaporin-4（AQP4）是星形胶质细胞的主要水通道，主要参与脑水肿的发展。乌司他丁（ULI）是一种有效的蛋白酶抑制剂，从新鲜的人尿中提取。我们假设，通过对脑AQP4进行分子靶向，ULI可能在急性HE中具有神经保护作用，而在脑中AQP4的表达可能被上调。为了诱发急性肝衰竭（ALF），大鼠被硫代乙酰胺（TAA）急性中毒。将动物随机分为HE和ULI治疗的HE组，对照组。总胆红素，白蛋白，血清氨基转移酶和血清/脑氨/促炎细胞因子，血脑屏障（BBB）完整性/紧密连接蛋白，评估大脑的水含量和神经学评分。另外，大脑AQP4和α-SyntrophinmRNA表达和蛋白质水平分别通过实时定量PCR和酶联免疫吸附法进行评估。剥去脑和肝组织，进行进一步的显微镜和组织学分析。ULI可能通过消炎活性发挥了潜在的双重神经/肝保护作用，改善了神经学评分，改善了动物的存活率，减轻了脑水肿，保持了血脑屏障的完整性，下调了AQP4的表达，并通过降低了α-syntrophin的水平使细胞膜极化。拯救了大脑的生物能。在ALF的HE中，可以将ULI作为可能的治疗选择。

图形概要