Protective effect of vitamin D on mice with atopic dermatitis
Objective To investigate the protective effect of vitamin D on atopic dermatitis mice,and its mechanism.Methods Fifty male BALB/c mice in clean grade were randomly divided into blank group,model group,control group and experimental-L group,experimental-H group,10 rats in each group.Except for the blank group,mice in the other groups were modeled with 2,4-dinitrofluorobenzene(DNCB).After modeling,mice in experimental-L and experimental-H groups were evenly smeared with 5 and 10 μg·kg-11,25(OH)2D3 on their backs every day,respectively;control group were evenly coated with hydrocortisone solution(1 mg·cm-2)twice a day for 10 days,and the mice in blank group and model group were coated with the same amount of 0.9%NaCl every day.After the administration,the skin lesions were evaluated,and orbital blood was collected and the back skin tissues were collected for use.The epidermal thickness was observed by hematoxylin-eosin staining,and the number of mast cells was detected by toluidine blue staining.The expression levels of serum immunoglobulin E(IgE),interleukin(IL)-13,IL-4,IL-17 were detected by enzyme-linked immunosorbent assay(ELISA),and the proportion of serum Th1 and Th2 cells were detected by flow cytometry.The expression of histamine type 1 receptor(HIR),protease activating receptor 2(PAR2),transient receptor potential vanillin 1(TRPV1)in back skin was detected by immunohistochemistry.Results The symptom scores of mice in blank group,model group,experimental-L group,experimental-H group and control group were 0,(8.50±1.12),(6.34±0.54),(3.91±0.29)and(3.79±0.53)points;the epidermal thickness of the back skin were(42.05±4.14),(77.65±7.02),(61.12±5.02),(55.34±4.13)and(52.19±3.08)μm;the number of mast cells in back tissue were(4.67±0.27),(32.16±2.49),(25.23±2.07),(18.13±1.46)and(15.37±1.29)number·mm-2;Th1/Th2 cell ratios were 2.76±0.28,0.36±0.06,1.02±0.18,2.05±0.14 and 2.07±0.29,respectively;HIR expression levels were 0.05±0.00,0.21±0.02,0.16±0.02,0.10±0.01 and 0.08±0.01;the expression levels of PAR2 were 0.05±0.01,0.19±0.01,0.12±0.01,0.09±0.01 and 0.07±0.01;the expression levels of TRPV1 were 0.05±0.01,0.25±0.03,0.15±0.01,0.10±0.01 and 0.09±0.00,respectively.The above indicators,experimental-L group,experimental-H group and control group were compared with model group;experimental-H group compared with experimental-L group,the differences were all statistically significant(all P<0.05).Conclusion Vitamin D can reduce DNCB induced atopic dermatitis by regulating Th1/Th2 cell balance,which may be related to the TRPV1 oxygen signaling pathway mediated by HIR and PAR2.
vitamin Datopic dermatitisTh1/Th2 balancemast cellsmechanism of action