Studies On Anti-delayed Type Hypersensitivity Of Glycyrrhetic Acid And Its Mechanism Of Action

Objective: In this paper,we explored the effects of Glycyrrhetic acid cream(GA)on delayed type hypersensitivity(DTH),and the mechanisms of GA in improving the symptom of DTH.Method:The cytotoxicity of GA to mouse organ and its inhibition effect of proliferation to lymphocyte in vitro by MTT assay.We detected the cytotoxicity of GA to mouse Spleen cells in vitro,and the inhibition effect of GA to mouse T lymphocyte proliferation induced by ConA,mouse B lymphocyte proliferation induced by LPS.By applying different concentrations of GA(0.5%,1%,2%),we observed its influence on weight changes,ear swelling,weight difference of ear swelling,ear morphology,spleen index.The content of IL-1? in serum was detected by enzyme linked immunosorbent assay(ELISA).The mRNA expression of IFN-?,ROR-?t,IL-6 and IL-17 a mRNA in mouse spleen and ear was semi-quantified by reverse transcription PCR(RT-PCR).Results:The results of MTT assay showed that GA almost had non-toxic to spleen lymphocytes in 24 and 48 hours in vitro(CC50 > 1mmol/L),In contrast,the CC50 of mycophenolate mofetil(MMF)were 22.32 ?mol/L at the same time.GA inhibited ConA-induced splenic T lymphocyte proliferation and showed a certain time and dose dependence in 24,48 and 72 hours,these results were similar to MMF in 48 and 72 hours.GA inhibited LPS-induced splenic B lymphocyte proliferation,however,the results were weaker than that of positive drug.These experiments prove that glycyrrhetic acid showed an obvious selective inhibition of T cell proliferation in vitro.Treatment of GA to DTH.In the results,GA increased the weight losing of mice and decreased the weight of ear swelling,the weight of ear swelling,sleen index compared with model group.H&E staining of ear biopsy revealed that there was significant infiltration of inflammatory cells in interstitial edema and the basal layer and spinous layer of epidermal in model group,however,the medium and high group of GA could reduce the surface damage,tissue edema and infiltration of inflammatory cells.These results indicated that GA could treat DTH of mice in a degree.The results of ELISA and RT-PCR showed that GA at indicated concerntration could reduced the expression of IL-1?,IFN-?,IL-6 and IL-17 a mRNA compared with model group.These results suggested that GA could play a role of immunosuppression,reduce inflammation reaction,alleviate the body immune state of hyperthyroidism.Conclusion: In conclusion,GA has the prospect to be developed into anti-inflammatory and immuno-suppressive drug.