الملخص
[Objective]To explore the degranulation effect and mechanism of Saposhnikovia divaricata(SD)extract on rat basophilic leukemia cell line RBL-2H3 cell.[Methods]Methylthialazole tetrazolium(MTT)test was used to select the concentrations in the subsequent experiments based on impact of 5,25,50,100,200,400 μg·mL-1 SD extract on the activity of RBL-2H3 cells.Immunoglobulin E(IgE)induction was used to establish RBL-2H3 cell degranulation model.Blank control group,model group,low dose SD extract group(5 μg·mL-1),medium dose SD extract group(25 μg·mL-1),high dose SD extract group(50 μg·mL-1)and dexamethasone(DXMS)group(100 μg·mL-1)were set up,with intervention for 30 minutes.MTT test was used to detect the effect of low,medium,high-dose SD extract on activity of RBL-2H3 cell degranulation model.Toluidine blue staining was used to observe the morphology of degranulation cells and calculate degranulation rates.Immunofluorescence staining was used to detect expression of F-actin.Enzyme linked immunosorbent assay(ELISA)was used to detect the levels of β-aminohexosidase,histamine,interleukin-4(IL-4),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ).Western blot was used to detect the expressions of phosphatidylinositide-3 kinase(PI3K),phosphorylation-PI3K(p-PI3K),protein kinase B(AKT),phosphorylation-AKT(p-AKT),p38 mitogen activated protein kinase(p38MAPK),phosphorylation-p38MAPK(p-p38MAPK),nuclear factors-κB(NF-κB),phosphorylation-NF-κB(p-NF-κB),extracellular regulated kinases(ERK)and phosphorylation-ERK(p-ERK)protein.[Results]The low,medium,high doses of SD extract(5,25,50 μg·mL-1)had no significant effects on the activity of RBL-2H3 cells(P＞0.05).Compared with blank control group,the number of toluidine blue stained cells of model group was decreased,cells shape rounded,degranulation rate was increased,expression of F-actin was decreased,the levels of β-aminohexosidase,histamine,IL-4,IL-6,TNF-α were increased,IFN-γ level was decreased,the expressions of p-PI3K/PI3K,p-AKT/AKT,p-p38MAPK/p38MAPK,p-NF-κB/NF-κB and p-ERK/ERK were increased(P＜0.01).Compared with model group,the F-actin expression of low,medium,high doses of SD extract groups and DXMS group was increased,levels of β-aminohexosidase,histamine,IL-4,IL-6 and TNF-α were decreased,IFN-γ level was increased(P＜0.01),the expressions of p-PI3K/PI3K,p-AKT/AKT,p-p38MAPK/p38MAPK,p-NF-κB/NF-κB and p-ERK/ERK were decreased(P＜0.05,P＜0.01);the number of toluidine blue stained cells in medium,high dose SD extract groups and DXMS group was increased with spindle cell shape,degranulation rate was decreased(P＜0.01).Compared with low dose SD extract group,degranulation rate of high dose SD extract group and DXMS group was decreased(P＜0.01),F-actin expression was increased(P＜0.05),p-p38MAPK/p38MAPK expressions were decreased(P＜0.01).[Conclusion]SD extract inhibited degranulation of IgE sensitized RBL-2H3 cell and decreased the levels of inflammatory mediators,its mechanism may be related to the inhibition the phosphorylation expression of PI3K/AKT,p38MAPK/NF-KB and ERK.