基于网络药理学探讨银杏叶提取物改善砷暴露所致肝胰岛素抵抗的效果

Effect of Ginkgo biloba extract on improving hepatic insulin resistance induced by arsenic exposure based on network pharmacology

  • 摘要:
    背景 砷暴露是我国常见的重要环境与职业有害因素,砷暴露所致的胰岛素抵抗(IR)对人群健康危害已引起广泛关注。
    目的 基于过氧化物酶体增殖物激活受体γ(PPARγ)/葡萄糖转运蛋白4(GLUT4)通路探讨砷暴露所致肝脏IR的部分机制,并探讨银杏叶提取物(GBE)对砷暴露所致肝脏IR的作用及其机制。
    方法 通过网络药理学预测药物的作用靶点进行分析,并进行体内外实验验证。体内实验:将48只SPF级C57BL/6J雄性小鼠分为对照组、50 mg·L−1 NaAsO2模型组(NaAsO2)、50 mg·L−1 NaAsO2+10 mg·kg−1 GBE干预组(NaAsO2+GBE)、10 mg·kg−1 GBE共4组,每组12只。染毒方式为自由饮用含50 mg·L−1 NaAsO2的纯净水,干预方式为每周1次腹腔注射含10 mg·kg−1 GBE的生理盐水。染毒6个月后,进行血糖检测、腹腔注射葡萄糖耐量实验(IPGTT)、胰岛素耐量实验(ITT)等实验,处死小鼠后取血清及肝脏组织,肝脏组织病理切片,酶联免疫吸附实验(ELISA)检测血清胰岛素水平、肝脏组织糖原含量及葡萄糖含量,蛋白免疫印记(WB)检测PPARγ及GLUT4蛋白表达。体外实验:使用肝癌细胞(HepG2)细胞,分为对照组、8 μmol·L−1 NaAsO2组(NaAsO2)、8 μmol·L−1 NaAsO2+200 mg·L−1 GBE干预组(NaAsO2+GBE)、200 mg·L−1 GBE组(GBE),共4组。ELISA法检测细胞糖原及葡萄糖水平,WB法检测PPARγ及GLUT4蛋白表达。
    结果 网络药理学发现GBE和PPARγ具有强烈的结合效应。体内实验中,小鼠的一般指标及血糖相关指标提示,与对照组相比,NaAsO2组血糖水平升高,而NaAsO2+GBE组小鼠血糖水平低于NaAsO2组(P<0.01)。病理切片提示,砷暴露组(NaAsO2组和NaAsO2+GBE组)肝脏结构损伤较重,染色深浅不一,部分肝细胞坏死并有弥漫性红细胞出现。体外实验及体内实验发现,与对照组相比,NaAsO2组糖原合成的能力及葡萄糖摄取的能力下降,而NaAsO2+GBE组可以改善这个状况,差异有统计学意义(P<0.01);WB法发现PPARγ表达受到了抑制,细胞膜上的GLUT4水平降低,而这些改变在NaAsO2+GBE组中均有缓解,差异有统计学意义(P<0.01)。
    结论 本研究结果提示GBE通过调控PPARγ/GLUT4通路拮抗砷暴露所致的肝脏IR,GBE对砷暴露所致肝脏IR具有一定保护作用,PPARγ可能是砷暴露所致肝脏IR的潜在治疗靶点。

     

    Abstract:
    Background Arsenic exposure is a common and important environmental and occupational hazardous factor in China, and arsenic-induced insulin resistance (IR) has attracted widespread attention as a negative health outcome to the population.
    Objective To explore part of the mechanism of hepatic IR induced by arsenic exposure based on the peroxisome proliferators-activated receptors γ (PPARγ)/ glucose transporter 4 (GLUT4) pathway, and to investigate potential effects of Ginkgo biloba extract (GBE) on hepatic IR induced by arsenic exposure and associated mechanism of action.
    Methods The target of drug action was predicted by network pharmacology and verified by in vivo and in vitro experiments. In vivo experiments: 48 SPF C57BL/6J male mice were divided into 4 groups, including control group, 50 mg·L−1 NaAsO2 model group (NaAsO2), 50 mg·L−1 NaAsO2+10 mg·kg−1 GBE intervene group (NaAsO2+GBE), and 10 mg·kg−1 GBE group (GBE), 12 mice in each group. The animals were given free access to purified water containing 50 mg·L−1 NaAsO2, or given intraperitoneal injection of normal saline containing 10 mg·kg−1 GBE once per week. After 6 months of exposure, blood glucose detection, intraperitoneal glucose tolerance test (IPGTT), and insulin tolerance test (ITT) were performed. Serum and liver tissues were collected after the mice were neutralized, liver histopathological sections were obtained, serum insulin levels, liver tissue glycogen content, glucose content were detected by enzyme linked immunosorbent assay (ELISA), and the expression of PPARγ and GLUT4 proteins was detected by Western blot (WB). In vitro experiments: HepG2 cells were divided into 4 groups, including control group, 8 μmol·L−1 NaAsO2 group (NaAsO2), 8 μmol·L−1 NaAsO2 + 200 mg·L−1 GBE intervene group (NaAsO2+GBE), and 200 mg·L−1 GBE group (GBE). The levels of glycogen and glucose were detected by ELISA, and the expression of PPARγ and GLUT4 proteins was detected by WB.
    Results  A strong binding effect between GBE and PPARγ was revealed by network pharmacology. In in vivo experiments, the NaAsO2 group exhibited an elevated blood glucose compared to the control group, and the NaAsO2+GBE group showed a decreased blood glucose compared to the NaAsO2 group (P<0.01). The histopathological sections indicated severe liver structural damage in the arsenic exposure groups (NaAsO2 group and NaAsO2+GBE group), with varying staining intensity, partial liver cell necrosis, and diffuse red blood cell appearance. Both results of in vitro and in vivo experiments showed a decrease in glycogen synthesis and glucose uptake in the NaAsO2 groups compared to the control groups, which was alleviated in the NaAsO2+GBE group (P<0.01). The results of WB revealed inhibited PPARγ expression and reduced GLUT4 levels on the cell membrane, and all these changes were alleviated in the NaAsO2+GBE group (P<0.01).
    Conclusion This study findings suggest that GBE antagonizes arsenic exposure-induced hepatic IR by regulating the PPARγ/GLUT4 pathway, indicating that GBE has a protective effect on arsenic exposure-induced hepatic IR, and PPARγ may be a potential therapeutic target for arsenic exposure-induced hepatic IR.

     

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