Ameliorative Effect of Gramine on 2，4-Dinitrochlorobenzene-Induced Atopic Dermatitis in Mice / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the pharmacodynamic effect of gramine on 2，4-dinitrochlorobenzene （DNCB）-induced atopic dermatitis （AD） in mice and its potential mechanism. MethodThe mice were divided into the normal control group， model group， dexamethasone （0.05 g·kg-1） group， and high- and low-dose （0.12，0.06 g·kg-1） gramine groups. Mice in all groups except for the normal control group were stimulated with DNCB， followed by medication 13 d later. The changes in skin lesions were then observed， and the skin thickness， moisture content， and transepidermal water loss （TWEL） in each group were measured. The pathological changes in skin lesions were observed by hematoxylin-eosin （HE） staining， and the effects of drugs on CD4+/CD8+T-cell ratio in the spleen were detected by flow cytometry. The levels of immunoglobulin E （IgE）， interleukin （IL）-4， and IL-6 in serum were detected by enzyme-linked immunosorbent assay （ELISA）， and the changes in serum alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， blood urea nitrogen （BUN）， and creatinine （CRE） by microplate method. The mRNA expression levels of inflammatory cytokines γ-interferon（IFN-γ）， IL-13， IL-17， IL-1β， IL-6， and tumor necrosis factor-α （TNF-α） in skin lesions were assayed by real-time polymerase chain reaction （Real-time PCR）， and the protein expression levels of nuclear transcription factor -κB (NF-κB) and NF-κB inhibitory protein α (IκBα) in skin lesions by Western blot. ResultCompared with the normal control group， the model group showed skin edema， erythema， scab， scratch， and lymphocyte and neutrophil infiltration， decreased skin moisture content， as well as increased skin thickness， TWEL （P<0.01）， spleen index， CD4+/CD8+ T-cell ratio in the spleen （P<0.05）， mRNA expression of IFN-γ， IL-13， IL-17， IL-1β， IL-6， and TNF-α in the skin lesions （P<0.05）， serum contents of IgE， IL-4， and IL-6 （P<0.05）， and protein expression of IκBα and NF-κB in skin lesions （P<0.05）. Compared with the model group， dexamethasone and gramine at different doses alleviated skin erythema， scale， scab， and inflammatory cell infiltration， elevated skin moisture content， inhibited skin thickening and TWEL， and decreased spleen index， CD4+/CD8+T-cell ratio in the spleen， mRNA expression of inflammatory factors in the skin lesions， serum contents of IgE and inflammatory factors， and protein expression of IκBα and NF-κB in skin lesions， especially in the dexamethasone group and the high- dose gramine group（P<0.05，P<0.01）. ConclusionGramine can inhibit the expression of related inflammatory factors and regulate the immune function of AD mice via the IκBα/NF-κB pathway， enabling it become a potential drug for treating AD.