Chen Z, Xu Y-Y, Wu R, Han Y-X, Yu Y, Ge J-F, Chen F-H
Anhui Key Laboratory of Bioactivity of Natural Products, School of Pharmacy, Anhui Medical University, Hefei, China.
Department of Pharmacy, The Fourth People's Hospital in Hefei, Hefei, China.
J Neuroendocrinol. 2017 Apr;29(4). doi: 10.1111/jne.12462.
Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, resulting not only in liver dysfunction, glucose and lipid metabolism disorder, but also in neuropsychiatric damage. In the present study, a NAFLD rat model was established via feeding of a high-fat diet, and behaviour was observed via the open field test (OFT), the sucrose preference test (SPT), the elevated plus maze (EPM), the forced swimming test (FST) and the Morris water maze (MWM). The plasma concentrations of alanine aminotransferase (ALT), glucose, free fatty acid (FFA), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were detected using chemiluminescence technique. The plasma levels of nesfatin-1, leptin and insulin were measured via enzyme-linked immunosorbent assay, and the protein expressions of p-glycogen synthase kinase-3β (GSK-3β), GSK-3β, p-β-catenin, β-catenin, cyclinD and copine 6 in the hippocampus and prefrontal cortex (PFC) were detected using western blotting. After 4 consecutive weeks of feeding with a high-fat diet, the rats showed obesity; increased plasma concentrations of ALT, glucose, FFA, TC, TG, HDL-C and LDL-C; decreased plasma levels of leptin and insulin; and inflammation and mild hepatocyte steatosis in the liver. Although there was no significant difference between groups with regard to performance in the OFT, EPM or FST, the NAFLD rats showed a decreased sucrose preference index in the SPT and impaired learning and memory in the MWM task. Moreover, the present study provides the first evidence of an increased plasma nesfatin-1 concentration in NAFLD rats, which was significantly correlated with plasma lipid concentrations and behavioural performance. Furthermore, copine 6 and p-β-catenin protein expression decreased and p-GSK-3β increased in the hippocampus and PFC of NAFLD rats. These results suggest that consuming of a high-fat diet for 4 consecutive weeks could successfully induce a NAFLD rat model. More importantly, these results provide the first evidence that impaired learning and memory in NAFLD rats was, at least partly, associated with increased plasma nesfatin-1 concentration and decreased copine 6 expression in the hippocampus and PFC.
非酒精性脂肪性肝病（NAFLD）是慢性肝病最常见的病因，不仅会导致肝功能障碍、糖脂代谢紊乱，还会造成神经精神损害。在本研究中，通过高脂饮食喂养建立了NAFLD大鼠模型，并通过旷场试验（OFT）、蔗糖偏好试验（SPT）、高架十字迷宫试验（EPM）、强迫游泳试验（FST）和莫里斯水迷宫试验（MWM）观察大鼠行为。采用化学发光技术检测血浆中丙氨酸氨基转移酶（ALT）、葡萄糖、游离脂肪酸（FFA）、总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）的浓度。通过酶联免疫吸附测定法检测血浆中nesfatin-1、瘦素和胰岛素水平，并用蛋白质免疫印迹法检测海马和前额叶皮质（PFC）中p-糖原合酶激酶-3β（GSK-3β）、GSK-3β、p-β-连环蛋白、β-连环蛋白、细胞周期蛋白D和Copine 6的蛋白表达。连续4周高脂饮食喂养后，大鼠出现肥胖；血浆中ALT、葡萄糖、FFA、TC、TG、HDL-C和LDL-C浓度升高；血浆中瘦素和胰岛素水平降低；肝脏出现炎症和轻度肝细胞脂肪变性。尽管在OFT、EPM或FST试验中，各组大鼠的表现没有显著差异，但NAFLD大鼠在SPT试验中的蔗糖偏好指数降低，在MWM任务中的学习和记忆能力受损。此外，本研究首次证明NAFLD大鼠血浆中nesfatin-1浓度升高，且与血浆脂质浓度和行为表现显著相关。此外，NAFLD大鼠海马和PFC中Copine 6和p-β-连环蛋白的蛋白表达降低，p-GSK-3β表达升高。这些结果表明，连续4周高脂饮食可成功诱导NAFLD大鼠模型。更重要的是，这些结果首次证明，NAFLD大鼠学习和记忆能力受损至少部分与海马和PFC中血浆nesfatin-1浓度升高及Copine 6表达降低有关。
