Experimental Study Of Suppressive Effect On Mice Contact Hypersensitivity And Regulation Of Type 1/type 2 Responses By Glycyrrhizin

Objective:To study the suppressive effect of glycyrrhizin (GL), a Chinese medicine, on contact hypersensitivity (CHS) induced by 2,4-dinitrofluorobenzene (DNFB). To explore the immunological mechanism that GL suppress contact hypersensitivity response, studies were performed on the accommodation between type 1 cytokines (IFN-γ, IL-2, TNF-α) and type 2 cytokines (IL-4, IL-10) in culture supernatants of skin-draining lymph node cells (LNC) prepared from sensitized mice (5 days post-DNFB-sensitization).Methods:BALB/c mice were divided into 5 groups according to different medication: glycyrrhizin 1 (11mg/kg) group, glycyrrhizin 2 (22mg/kg) group, glycyrrhizin 3 (44mg/kg) group, dexamethasone (0.75mg/kg) group, and normal saline group. For induction of CHS to DNFB, mice were sensitized to abdomen and challenged to right ear by epicutaneously DNFB. Each mouse were administrated intraperitoneally on day -1 to day 5, day -1 and day 0, day 4 and day 5 with different medication. The suppression of mice CHS by different medication were evaluated 24 hours after elicited, according to ear thickness difference, ear weight difference and pathological change of challenged ear section. Thymus index and spleen index were calculated to see the effect on mice lymph organs to CHS. Skin-draining LNCs were obtained from sensitized mice (5 days post-DNFB-sensitization) stimulated with Staphylococcal enterotoxin B (SEB). Next, culture supernatants were collected, and the concentrations of cytokines (IFN-γ, IL-2, TNF-α, IL-4, IL-10) were quantitated by Luminex^TM100. Results:Compared with CHS group, the ear thickness difference and ear weight difference were both significantly reduced in GL1, GL2, GL3 and DXM groups (P<0.01). Simultaneously histological edema and infiltration of inflammatory cells...