银杏叶提取物对肥大细胞活化的影响

目的： 观察银杏叶提取物（EGB）对肥大细胞活化脱颗粒的影响。方法：动物实验分为6个组，分别是正常对照组、空白对照组、EGB高（30 mg/kg）、中（10 mg/kg）、低（3 mg/kg）剂量组及阳性药物对照组（氮卓斯汀，5 mg/kg），通过大鼠被动皮肤过敏反应（PCA）实验，用比色测定法检测EGB在体内对肥大细胞(MC)影响；细胞实验分为6个组，分别是正常对照组、空白对照组、EGB高（200 mg/L）、中（100 mg/L）、低（50 mg/L）剂量组及阳性药物对照组（氮卓斯汀，30 mg/L），然后分别将其加入抗原致敏的（DNP-HSA, 200 μg/L 培养过夜）RBL-2H3细胞中，观察EGB对RBL-2H3细胞脱颗粒、炎症介质释放及Akt、p38磷酸化的影响。结果： 动物实验显示，EGB高（30 mg/kg）、中（10 mg/kg）剂量组能明显抑制大鼠PCA。细胞实验显示，EGB高（200 mg/L）、中（100 mg/L）、低（50 mg/L）剂量组均能抑制RBL-2H3细胞脱颗粒；EGB高（200 mg/L）、中（100 mg/L）剂量组能抑制RBL-2H3细胞释放组胺、白细胞三烯C4（LTC4）、白细胞介素4（IL-4）及肿瘤坏死因子α(TNF-α)；EGB高（200 mg/L）、中（100 mg/L）剂量组能抑制Akt和p38的磷酸化。结论： EGB的抗过敏作用与其能抑制肥大细胞的脱颗粒以及抑制组胺、白细胞三烯C4、肿瘤坏死因子α、白细胞介素4炎症介质释放有关；EGB抑制肥大细胞的活化可能与其抑制Akt和p38的活性相关。

Effect of extracts of ginkgo biloba leaves on activation of RBL-2H3 cells

AIM: To investigate the mechanism of extracts of ginkgo biloba leaves (EGB) on degranulation from mast cells. METHODS: Wistar rats were randomly divided into 6 groups, including normal group, control group, high dose of EGB group (30 mg/kg), moderate dose of EGB group (10 mg/kg), low dose of EGB group (3 mg/kg) and positive control medicine group (azelastine, 5 mg/kg), each group had 10 rats (half female and half male). The experiment of passive cutaneous anaphylaxis reaction (PCA) and colorimetry were used to determine the effect of EGB on degranulation of mast cells in vivo. For in vitro study, various doses of EGB (200 mg/L, 100 mg/L and 50 mg/L) were added to the culture medium of RBL-2H3 cells cultured with 200 μg/L of dinitrophenyl (DNP) specific IgE overnight. The azelastine (30 mg/L) was selected as the positive control. The antigen (DNP-human serum albumin, DNP-HSA, 20 μg/L)-induced release of degranulation was measured by enzymatic assay, histamine by EIA, leucotriene C4 (LTC4), interleukin-4(IL-4) and tumor necrosis factor-α (TNF-α) by ELISA, respectively. In addition, the effect of EGB on phosphorylation of Akt and p38 was observed by Western blotting. RESULTS: The results showed that treatments with high dose of EGB (30 mg/kg) and moderate dose of EGB (10 mg/kg) were followed by a decrease in PCA of rats. All doses of EGB (200 mg/L, 100 mg/L and 50 mg/L) obviously suppressed the degranulation from RBL-2H3 cells, whereas results in high dose group (200 mg/L) and moderate dose of EGB group (100 mg/L) indicated significantly inhibitory effect on β-hexosaminidase, histamine, LTC4, IL-4,TNF-α, phosphorylation of Akt and p38 of RBL-2H3 cells induced by antigen. CONCLUSION: EGB may suppress the anaphylactic reaction by inhibiting the action of mast cells. Akt and p38 at least in part contribute to this event.