目的 探讨石榴花提取物（Punica granatum flower extract，PFE）及其活性成分白桦脂酸和木犀草素对棕榈酸诱导的人肝癌HepG2细胞脂质沉积的改善作用和作用机制。方法 通过CCK-8法测定棕榈酸、辛伐他汀、PFE、白桦脂酸和木犀草素对HepG2细胞活力的影响，以确定后续给药剂量。利用500 μmol/L棕榈酸建立HepG2细胞脂质沉积模型，同时给予PFE（50、100、200 mg/L）、白桦脂酸（40、80、160 μmol/L）、木犀草素（40、80、160 μmol/L）进行干预，采用油红O染色法测定细胞内脂质含量；GPO-PAP法测定细胞内三酰甘油（triglyceride，TG）和总胆固醇（Total cholesterol，TC）含量；流式细胞仪检测早、晚期凋亡细胞率；Western blotting检测凋亡因子B淋巴细胞瘤-2（B-cell lymphoma-2，Bcl-2）、Bcl-2相关X蛋白（Bcl-2 associated X protein，Bax）及磷脂酰肌醇3-激酶/蛋白激酶B（phosphatidylinositol 3-kinase/protein kinase B，PI3K/Akt）、Janus激酶2/信号传导及转录激活因子3（Janus kinase 2/signal transducer and activator of transcription 3，JAK2/STAT3）通路相关蛋白表达；qRT-PCR测定PI3K、Akt、JAK2、STAT3的mRNA表达。结果 选取对细胞活力无显著影响的PFE（50、100、200 mg/L）、白桦脂酸（40、80、160 μmol/L）和木犀草素（40、80、160 μmol/L）进行后续实验。与对照组比较，模型组细胞内脂质、TC和TG含量均显著升高（P＜0.001），细胞凋亡率显著升高（P＜0.001），PI3K、Akt、Bax蛋白和PI3K、Akt mRNA表达水平均显著升高（P＜0.001），JAK2、STAT3、Bcl-2蛋白和JAK2、STAT3 mRNA表达水平均显著下降（P＜0.001）。与模型组比较，各给药组细胞内脂质、TC和TG含量均显著降低（P＜0.05、0.01、0.001），细胞早、晚期凋亡率显著下降（P＜0.01、0.001），细胞中PI3K、Akt、Bax蛋白和PI3K、Akt mRNA表达水平均显著降低（P＜0.05、0.001），JAK2、STAT3蛋白和mRNA表达水平均显著升高（P＜0.05、0.01、0.001），PFE组和白桦脂酸组Bcl-2蛋白表达水平均显著升高（P＜0.01、0.001）。结论PFE、白桦脂酸和木犀草素能够改善棕榈酸诱导的HepG2细胞脂质沉积，其作用机制与抑制游离脂肪酸诱导的细胞凋亡、调控PI3K/Akt和JAK2/STAT3通路有关。

Objective To investigate the effect and mechanism of Punica granatum flower extract (PFE) and its active components betulinic acid and luteolin on palmitic acid-induced lipid deposition in HepG2 cells. Methods CCK-8 method was used to determine the effects of palmitic acid, simvastatin, PFE, betulinic acid and luteolin on viability of HepG2 cells, so as to determine the subsequent dosage. Lipid deposition model of HepG2 cells was established with 500 μmol/L palmitic acid. At the same time, PFE (50, 100, 200 mg/L), betulinic acid (40, 80, 160 μmol/L) and luteolin (40, 80, 160 μmol/L) were given for intervention, and intracellular lipid content was measured by oil red O staining; The contents of triglyceride (TG) and total cholesterol (TC) in cells were determined by GPO-PAP method; The rate of early and late apoptotic cells was detected by flow cytometry; Western blotting was used to detect expressions of apoptosis factors B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway related proteins; The mRNA expressions of PI3K, Akt, JAK2 and STAT3 were determined by qRT-PCR. Results PFE (50, 100, 200 mg/L), betulinic acid (40, 80, 160 μmol/L) and luteolin (40, 80, 160 μmol/L) which had no significant effect on cell viability were selected for subsequent experiments. Compared with control group, the contents of lipid, TC and TG in cells of model group were significantly increased (P < 0.001), apoptosis rate was significantly increased (P < 0.001), PI3K, Akt, Bax proteins and PI3K, Akt mRNA expression levels were significantly increased (P < 0.001), JAK2, STAT3, Bcl-2 proteins and JAK2, Akt mRNA were significantly increased. Compared with model group, the contents of lipid, TC and TG in cells of each drug group were significantly decreased (P < 0.05, 0.01, 0.001), apoptosis rate in early and late stages were significantly decreased (P < 0.01, 0.001), PI3K, Akt and Bax proteins and PI3K, Akt mRNA expression levels in cells were significantly decreased (P < 0.01), JAK2, STAT3 protein and mRNA expression levels were significantly increased (P < 0.05, 0.01, 0.001), and Bcl-2 protein expression level in PFE group and betulinic acid group were significantly increased (P < 0.01, 0.001). Conclusion PFE, betulinic acid and luteolin could improve lipid deposition induced by palmitic acid in HepG2 cells, and its mechanism may be related to inhibiting apoptosis induced by free fatty acids and regulating PI3K/Akt and JAK2/STAT3 pathways.

R285.5

国家自然科学基金资助项目（81960697）；江西省教育厅科技重点项目（170699）；江西中医药大学科技创新团队发展计划（CXTD22002）