ABSTRACT
OBJECTIVE To study the intervention effect of Hippophae rhamnoides oil on glucocorticoid resistance in superantigen-induced atopic dermatitis （AD） mice，and to explore the mechanism of action. METHODS Fifty mice were randomly divided into 5 groups，i.e. normal control group （group A），model group （group B），dexamethasone intervention group （positive control，group C），H. rhamnoides oil intervention group （group D），dexamethasone+H. rhamnoides oil intervention group （group E），with 10 mice in each group. Except for group A，other groups were given 2，4-dinitrochlorobenzene+staphylococcal enterotoxin B to induce the AD mice model. Starting from the 7th day of the experiment，groups C，D and E were given dexamethasone （1.5 mg/kg） and/or H. rhamnoides oil （10 mL/kg） intragastrically，once a day，for 28 consecutive days. After the last medication，the pathomorphological changes of ear tissue were observed by 节作用。E-mail：57667478@qq.com HE staining； the serum levels of immunoglobulin E （IgE） and interleukin 4 （IL-4） were detected by enzyme-linked immunosorbent assay. Positive cell count of glucocorticoid receptor α （GRα） and GRβ in the ear tissue of mice was detected by tyramide signal amplification. The expressions of GRα protein，GRβ protein，and protein kinase B （AKT）/ribosomal protein S6 kinase 1，S6K1 （S6K1） signaling pathway-related proteins were determined by Western blot assay. RESULTS Compared with group B，the skin inflammation in the left ear of the mice was significantly reduced in groups C，D and E，the serum levels of IgE and IL-4 were decreased significantly in groups D and E （P＜ 0.05），while the number of GRα positive cells and GRα protein expression were increased significantly （P＜0.05）； the protein levels of G protein inhibitory subunit 1 （Gαi1），Gαi3，phosphorylated S6K1 （p-S6K1） and phosphorylated AKT （p-AKT） were decreased significantly （P＜0.05）； the number of GRβ positive cells and protein expression of GRβ was decreased significantly in group E（P＜0.05）. Compared with group C，the skin inflammation in the left ear of the mice was almost clear away in group E，the serum levels of IgE and IL-4 were decreased significantly （P＜0.05）； the number of GRα positive cells and GRα protein expression were increased significantly in groups D and E （P＜0.05）； the protein levels of GRβ，Gαi1，p-S6K1 and p-AKT were all decreased significantly in groups D and E（P＜0.05）； and protein level of Gαi3 was decreased significantly in group E （P＜0.05）. CONCLUSIONS H. rhamnoides oil has an intervention effect on superantigen-induced glucocorticoid resistance of AD mice，which may be exerted by inhibition of the Gαi1/3-induced AKT/S6K1 signaling pathway.