目的 探讨胡黄连主要有效成分胡黄连苷I、II对3T3-L1前脂肪细胞成脂分化的影响。方法 采用MTT法检测胡黄连苷I、II对3T3-L1细胞活力的影响，确定给药浓度；使用诱导分化培养基诱导3T3-L1细胞分化为成熟脂肪细胞，通过油红O染色法观察胡黄连苷I、II（20、40 μmol·L^-1）对细胞脂肪蓄积的影响；实时荧光定量PCR（qRT-PCR）法检测3T3-L1细胞脂肪合成相关的乙酰辅酶A羧化酶1（ACACA）、脂肪酸合酶（FASN）、硬脂酰辅酶A去饱和酶（SCD1）、脂肪酸结合蛋白（FABP4）和调节脂肪合成的转录因子过氧化物酶体增殖物激活受体γ（PPARγ）、固醇调节元件结合蛋白1（SREBP1）的mRNA表达水平；Western blotting实验检测CCAAT/增强子结合蛋白β（C/EBPβ）、SCD1和PPARγ的蛋白表达。结果 浓度低于50 μmol·L^-1的胡黄连苷I、II处理不会影响细胞的存活率；与对照组比较，模型组在诱导分化后细胞形态变圆，油红O染色显示细胞中有大量脂肪蓄积（P＜0.01）；与模型组比较，胡黄连苷I、II显著减少了脂肪蓄积（P＜0.01）。与对照组比较，模型组ACACA、FASN、SCD1、FABP4、PPARγ和SREBP1的mRNA表达均显著上调（P＜0.05、0.01）；与模型组比较，胡黄连苷I、II 20、40 μmol·L^-1均显著降低了ACACA、SCD1、FASN、FABP4、SREBP1 mRNA的表达（P＜0.05、0.01），胡黄连苷I、II仅在40 μmol·L^-1时显著抑制SREBP1 mRNA的表达（P＜0.05、0.01）。Western blotting结果显示，与对照组比较，模型组PPARγ、C/EBPβ和SCD1的蛋白表达显著上调（P＜0.01）；与模型组比较，胡黄连苷I、II各浓度均显著降低了SCD1蛋白的表达（P＜0.01），胡黄连苷I 40 μmol·L^-1和胡黄连苷II 20、40 μmol·L^-1组PPARγ、C/EBPβ蛋白的表达显著降低（P＜0.05、0.01）。结论 胡黄连苷I、II均可以显著抑制3T3-L1细胞的脂肪分化，并减少脂肪蓄积，胡黄连苷I表现出更好的剂量相关性，其作用机制可能与抑制C/EBPβ-PPARγ通路有关。

Objective To investigate the effects of picroside I and II, the main active components of Picrorhiza scrophulariiflora, on adipogenic differentiation of 3T3-L1 preadipocytes. Methods MTT assay was used to detect the effect of picroside I and II on the viability of 3T3-L1 preadipocytes, and to determine the concentration of drug administered. 3T3-L1 preadipocytes were induced to differentiate into mature adipocytes by differentiation medium. The effects of picroside I and picroside II (20 and 40 μmol·L^-1) on lipid accumulation were observed by oil red O staining. Real-time quantitative PCR (qRT-PCR) was used to detect the expression of Acetyl-CoA carboxylase 1 (ACACA), fatty acid synthase (FASN), Stearoyl-CoA desaturase (SCD1), fatty acid binding protein (FABP4), peroxisome proliferator-activated receptor gamma (PPARγ), and sterol regulatory element binding protein 1 (SREBP1) mRNA expression levels in 3T3-L1 preadipocytes. Western blotting assay was used to detected the protein expression of CCAAT/ enhancer binding protein β (C/EBPβ), SCD1, and PPARγ. Results The treatment of picroside I and II with concentration below 50 μmol·L^-1 does not affect the cell survival rate. Compared with control group, the vast majority of 3T3-L1 preadipocytes in the model group became circular after induced differentiation, and oil red O staining showed that there was a large amount of lipid accumulation in the cells (P < 0.01). Compared with model group, lipid accumulation was significantly reduced in the picroside I and II administration groups. Compared with the control group, the mRNA expression of ACACA, FASN, SCD1, FABP4, PPARγ and SREBP1 in the model group was significantly up-regulated (P < 0.05). Compared with model group, picroside I and II 20, 40 μmol·L^-1 significantly reduced the expression of ACACA, SCD1, FASN, FABP4, and SREBP1 mRNA (P < 0.05, 0.01), while picroside I and II 40 μmol·L^-1 significantly reduced the expression of SREBP1 mRNA (P < 0.05, 0.01). Western blotting results showed that, compared with control group, the protein levels of PPARγ, C/EBPβ, and SCD1 in the model group were significantly up-regulated (P < 0.01). Compared with model group, each concentration of picroside I and II significantly reduced the expression of SCD1 protein (P < 0.01), while the expression of PPARγ and C/EBPβ protein in picroside I 40 μmol·L^-1 and picroside II 20, 40 μmol·L^-1 group was significantly reduced (P < 0.05, 0.01). Conclusion Both picroside I and II can inhibit the adipose differentiation of 3T3- L1 preadipocytes, and reduce fat accumulation. Picroside I shows a better dose dependence, and their mechanism may be related to the inhibition of C/EBPβ-PPARγ pathway.

中央高校基本科研业务费专项资金资助项目（3332022063）；国家自然科学基金资助项目（82202950）；国家自然科学基金资助项目（82104012）；中国医学科学院医学与健康科技创新工程重大协同创新项目资助（2021-I2M-1-042）