The Correlated Study On Water Channel Protein 3 In The Lesions Of Eczema

Eczema is one of the most common inflammatory skin diseases. There is substantial clinical variation, but dry skin, pruritus and erythematous lesions are prominent feature. Attack generally last a few weeks, but because of the tendency to relapses the condition may persist for long periods. In eczema, pruritic and erythematous papules are consistent with inflammation. However, anther common sign, i.e. dry skin, may indicate involvement of other pathogenic mechanisms. But the etiology of eczema is unknown.The aquaporins (AQPs) are a family of transmembrane proteins forming water channels. In mammals, water transport through AQPs is important in kidney and other tissues involved in water transport. Some AQPs (aquaglyceroporins) also exhibit glycerol and urea permeability. Skin is the limiting tissue of the body and within skin, the stratum corneum (SC) of the epidermis is the limiting barrier to water loss by evaporation. The aquaglyceroporin AQP3 is abundantly expressed in keratinocytes of mammalian skin epidermis. Mice lacking AQP3 have dry skin and reduced SC hydration. Interestingly, however, results suggested that impaired glycerol, rather than water transport was responsible for this phenotype. In keratinocytes, the major cell type of the epidermis, only theaquaglyceroporins AQP3 was found. In the present work, we examined the overall expression of AQPs in cells from human skin and we reviewed data on the functional role of AQPs in skin, particularly in the epidermis.The experiment group selects the skin lesions of 20 eczema patients whose final diagnosis is through clinic, the control group selects 10 normal skins. Then we initiate the study of AQP3 through imunohistochemistry and immunofluorescence to observe. For indirect immunofluorescence, tissues were fixed in 4% paraformaldehyde, and washed in PBS. 5μm-thick cryosections were collected on glass slides. Slides were preincubated in PBS containing 1% BSA, then incubated in polyclonal rabbit serum containing antibodies against the C terminus sequence of AQP3. Following washes in PBS, slides were incubated with a secondary FITC conjugated anti rabbit antibody and washed in PBS again. Finally, slides were counter stained with Evans blue (red fluorescence), and observed at the fluorescence microscope. A positive rate was used to quantify the positivity of the staining. SPSS prob- ability was used as statistics method (p <0.05).In healthy skin, epidermal AQP3 immunoreactivity was weak and mainly found in the stratum basale. A gradient was formed with decreasing AQP3 staining in the lower layers of the stratum spinosum. By contrast, in eczema strong AQP3 staining was found in both the stratum basale and the stratum spinosum. Increased expression of AQP3 was found in eczema compared with healthy skin.In conclusion, AQP3 is the predominant aquaporin in human skin. Increased expression and altered cellular distribution of AQP3 is found in eczema and this may contribute to water loss. AQP3 may be important for water transport and hydration in human skin epidermis.Above studies, we can study the AQP3 in eczema lesions future by Western blot and the RT-PCR technology. Maybe it could provide the theoretical basis in gene and molecular level.