| BackgroundAtopic dermatitis(AD)is a chronic and eczema-like skin disease accompanied with inflammation and itching.It keeps a close connection with skin dysfunction and history of allergic diseases such as allergic rhinitis,conjunctivitis and bronchial asthma.AD usually diagnosed when patients are infants.According to researches,50%of AD patients are preschool children,but adults can also have AD.Severely itching can obviously reduce the life quality of AD patients.Although there is no evidence for national incidence rate of AD,some local area reports showed a gradually rising incidence rate of AD in last decades.According to the epidemiological statistics of Shanghai which reported in 2012,the prevalence of AD was 8.3%in children aged 3-6 and the prevalence of AD in urban areas was significantly higher than rural areas(10.2%and 4.6%,respectively).During 2006,the prevalence of AD children patients aged 0-6 years was 2.9%in Tianjin area.The pathogenesis of AD is complex and the mechanism is still unclear yet.Majority of researchers considered that AD is caused by genetic factors and environmental factors which is mainly related to the activation of T cells,cytokines,IgE,infection and super-antigen.The immune dysfunction of skin and changes of local cytokines may be more important than allergic factors.Recent studies reported that many plants polysaccharides and insect polysaccharides have significant function of antioxidant and anti-tumor.Polysaccharide of Chinese White Wax Scale is crucial in anti-tumor treatment because it can affect the function of immune cells,complement and reticuloendothelial system.Nowadays,there is few studies about the polysaccharide of Chinese White Wax Scale in the immune skin disease and the mechanism is still unclear,which needs to be researched further in the future.ObjectiveTo study the effect of polysaccharide of Chinses White Wax Scale in Dinitrochlorobenzene-induced AD mice model.MethodTwelve 6-week-old male BALB/c mice were randomly divided into two groups(six rats in each group).Including the experiment group treated with polysaccharide of Chinses White Wax Scale and the control group.All the mice were sensitized with DNCB through skin of ears and back to establish AD mice model.When starting to build the AD mice model,the experiment group was treated with 5%polysaccharide of Chinses White Wax Scale(lmg/g)while the control group was treated with equal volume of saline.The thickness of ears was measured in both groups.Their blood samples and skin specimens of all the mice were collected after 2 weeks.The level of IgE in serum was measured by ELSIA.The DNCB-damaged skins of mice were made into paraffin sections and stained by HE and toluidine blue.The changes of keratinocytes in epidermis layer and the infiltration of inflammatory cells in corium cutis were observed under microscope.The expression of IL-6,IFN-? and IL-17 in damaged skins were detected by RT-PCR.ResultsCompared to the control group,the ear thickness of the experiment group which treated with polysaccharide of Chinses White Wax Scale was decreased and the abnormal hyperplasia of the keratinocytes in the epidermis layer was significantly relieved.The level of IgE in serum is lower in the experiment group and its number of mast cells is less than the control group.The expression of IL-6,IFN-? and IL-17 in DNCB-damaged skins were decreased in the experiment group.ConclusionPolysaccharide of Chinses White Wax Scale can significantly relieve the symptoms of AD induced by DNCB and reduce the level of IgE in serum.It can also improve the proliferation of keratinocytes and decline the infiltration of mast cells.There are two possible mechanism of polysaccharide.On the one hand,it could decline the differentiation of Thl cells and Th17 cells.On the other hand,it could inhibit the expression of proinflammatory cytokines such as IL-6,IFN-y and IL-17 which can reduce the inflammatory response. |
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