Expression Of Antimicrobial Peptide In Mice With Atopic Dermatitis Was Injected By VitaminD₃

Objective:To establish the mouse model of atopic dermatitis by epicutaneoussensitizing Balb/c mice combined with intraperitoneal administration of OVA and dorsal skin pasted OVA.Observe the expression of antimicrobial peptide in mice with atopic dermatitis was intraperitoneal injection of 1,25-(OH)2D3.Methods:Forty female Balb/c mice were randomly divided into four groups(ten mice per group)as follows:normal group,model group,control group,and vitamin D group.OVA as an allergen establishes atopic dermatitis-like mouse models after the models were successfully established,the 1,25-(OH)2D3was intraperitoneally injected into the vitamin D group two weeks per day.The end of experimentthe mice were weighed,the SCORAD was evaluated,the number of scratches was recorded,the blood was taken from the eyeball and thenthe mice were sacrificed.Serum was obtained from the supernatants after centrifugation for ELISA.The concentrations of IgE,IL-4 and IFN-?in the serum were determined with ELISA kits,according to the manufacturer's instructions.The dorsal skin specimens were fixed in 10%formalin which were dissected,dehydrated,and embedded in paraffin.Multiple sectionswere mounted on slides.The sections on slides were stained with HE to analyze the thicknesses of the epidermis and dermis and the inflammatory infiltrate.Protein samples were prepared from the dorsal skin.By using western blot analyzed the expression of cathelicidin and mBD-2.Result:1.Morphological observation of mouse skin lesions:In the normal group,the skin of the mice showed normal,and there were changes in skin lesions such as erythema,scarring,and lichenification in the skin of other groups.Improvement in dermatitis after intraperitoneal injection of vitamin D3 was statistically significant compared with the model group and the control group;2.Serum IgE,IL-4 and IFN-y concentrations:IgE levels in the serum of the model group and control group increased significantly compared with the normal group(P<0.01),and serum IgE concentrations in the vitamin D group were lower than those in the control group(P<0.05).The levels of IL-4 in the model group and the control group were significantly higher than those in the normal group(P<0.01).Theexpression of IL-4 in the vitamin D group was lower than that in the control group(P<0.01).The levels of serum IFN-y in the normal group were significantly lower than those in the control group(P<0.01).The level of IFN-y in the vitamin D group was significantly higher than that in the control group(P<0.01).3.Expression of epidermal antimicrobial peptides:The expression of epidermal peptides in the skin tissue of each group of mice was detected by western blot.The results showed that cathelicidin and mBD-2 were not expressed in normal tissues,but expression was significantly increased in the skin of model and control mice.The expression level after injection of vitamin D injection was lower than that of the model group and the control group,and the difference was statistically significant(P<0.05).Conclusion:1.The OVA can contribute crucially to the AD-like cutaneous symptoms,such as thickened epidermis and dermis,inflammatory infiltration,exaggerated serum-IgE,and may predominance of Th2-type cytokines in serum.2.1,25-(OH)2D3 can relieve these OVA-induced AD-like symptoms and allergic responses through suppression of inflammatory infiltration.The expression of anti-microbial peptides is positively correlated with the degree of inflammation of dermatitis.Thus,it is still necessary to further study its regulation mechanism.