Objective: To study the anti-fibrotic effect of ghrelin on high-fat diet-induced non-alcoholic steatohepatitis (NASH) in mice. Methods: 24 male C57BL/6 mice were randomly divided into a normal diet group, a normal diet + ghrelin group, a high-fat diet group, and the high-fat diet + ghrelin group. The HFD and HFD+ghrelin groups were fed high-fat diet for 16 weeks to induce non-alcoholic steatohepatitis. Among them, the NCD+ghrelin group and HFD+ghrelin group were continuously given ghrelin intervention (11nmol·kg(-1)·d(-1)) for 2 weeks after feeding for 14 weeks. 16 mice were euthanized on weekends. The plasma levels of alanine aminotransferase (ALT) and hyaluronic acid (HA) were measured in mice. The content of hydroxyproline (Hyp) was determined in liver tissue. RT-qPCR was used to detect the mRNA expression levels of transforming growth factor β1 (TGF-β1) and collagen types I, III, and IV in liver tissue. A Western blot was used to detect the expression level of the α-smooth muscle actin (α-SMA) protein in liver tissue. HE staining was used to observe the morphological changes in liver tissue. VG staining was used to observe the fibrotic condition in liver tissue. Results: Compared with the NCD group, plasma ALT (266.80±146.80)U/L, HA (219.00±39.47) ng/ml levels, Hyp content (0.35±0.05)μg/mg prot (P < 0.05), mRNA expression levels of transforming growth factor β1 (TGF-β1) and collagen types I, III, IV (P < 0.05), and the expression level of α-SMA protein in the HFD group were significantly increased (P < 0.05), with congestion in the hepatic central lobular veins, hepatocytes swelling, and deposition of a large amount of collagen fibers in liver tissue. Compared with the HFD group, plasma ALT (57.17±20.88)U/L, HA (75.68±8.40)μg/mg levels, Hyp content (0.19±0.07)μg/mg prot, mRNA expression levels of transforming growth factor β1 (TGF-β1) and collagen types I, III, IV (P < 0.05), and the expression level of α-SMA protein in the HFD+ghrelin mice group was significantly reduced (P < 0.05), with only mild sinusoidal congestion in the liver tissue but significant improvement and reduction in liver injury and collagen fiber deposition. Conclusion: Ghrelin has a significant improvement effect on liver fibrosis in NASH mice.
目的： 研究胃饥饿素（Ghrelin）对高脂饮食诱导的非酒精性脂肪性肝炎（NASH）小鼠的抗纤维化作用。 方法： 24只雄性C57BL/6小鼠随机分为正常饮食（NCD）组、NCD+Ghrelin组、高脂饮食（HFD）组和HFD+Ghrelin组。HFD组及HFD+Ghrelin组给予高脂饲料喂养16周诱发NASH，其中NCD+Ghrelin组及HFD+Ghrelin组于喂养14周后，持续给予Ghrelin干预(11 nmol·kg(-1)·d(-1)) 2周。16周末处死动物。检测小鼠血浆丙氨酸转氨酶（ALT）、透明质酸（HA）水平；测定肝组织羟脯氨酸（Hyp）含量；RT-qPCR检测肝组织转化生长因子β1（TGF-β1）及Ⅰ、Ⅲ、Ⅳ型胶原mRNA表达水平；Western blot检测肝组织α-平滑肌肌动蛋白（α-SMA）蛋白表达水平；苏木精染色观察肝组织形态学变化，VG染色观察肝组织纤维化的情况。 结果： NCD组ALT、HA、Hyp分别为（19.17±3.71）U/L、（80.58±27.27）ng/ml、（0.20±0.06）μg/mg与NCD组比较，HFD组血浆ALT (266.80±146.80)U/L、HA (219.00±39.47)ng/ml水平显著升高（P < 0.05），肝组织Hyp (0.35±0.05)μg/mg prot含量增加（P < 0.05），TGF-β1及Ⅰ、Ⅲ、Ⅳ型胶原mRNA表达水平显著升高（P < 0.05），α-SMA蛋白表达水平明显增加，肝小叶中央静脉淤血、肝细胞肿胀，肝组织大量胶原纤维沉积。与HFD组比较，HFD+Ghrelin组小鼠血浆ALT (57.17±20.88)U/L 、HA (75.68±8.40)μg/mg水平、肝组织Hyp (0.19±0.07)μg/mg prot含量明显降低（P < 0.05），TGF-β1、Ⅰ、Ⅲ、Ⅳ型胶原mRNA表达水平均降低（P < 0.05）；HFD+Ghrelin组α-SMA的蛋白表达水平下降（P < 0.05）。肝组织内仅见血窦轻度淤血，肝损伤明显改善，胶原纤维沉积显著减少。 结论： Ghrelin对NASH小鼠的肝纤维化具有明显的改善作用。.
Keywords: Ghrelin; NASH; liver fibrosis.