OBJECTIVE

2

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

2

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 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

2

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

2

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.