| BackgroundNude mice is a type of indispensable model mice at present in the field of biologically medical research. It can be widely used in the oncology, toxicology, safety evaluation of drugs and biological products as well as the screening researchs. In contrast to the wild-type mice, nude mice has an immune deficiency, and it also can be used as receptors of skin grafting, which has been widely applied in skin tissue engineering research as well. The causes and development of skin disease can be researched by nude mice model. However, the comparative researchs for the skin histological structure between nude mice and wild-type mice is few. As a result, it is extremely important to conduct a detailedly comparative research in histological structure of skin between the nude mice and wild-type mice.ObjectTo investigate the differences of skin morphologic structure and the distribution, quantity of epithelial stem cell markers expression between adult nude mice and wild-type mice skin.MethodsThe dorsal skins of 8 adult nude mice (Balb/c-nu) and 8 wild-type mice (Kunming mice) were taken respectively and then sectioned for subsequent use after fixation, dehydration, transparency, paraffin-Embedded.1. Hematoxylin-Eosin staining:Hematoxylin-Eosin(HE) staining was used to observe the morphological structure of epidermis, dermis and cutaneous appendages of nude mice and wild-type mice skin.2. Immunofluorescence:Immunofluorescence with special antibody was to determine the distribution of epithelial stem cell markers p63, β1 integrin and keratin 19 (K.19) expression in the skin of nude mice and wild-type mice.3. Immunochemistry:Immunochemistry with special antibody was to examine the quantity of epithelial stem cell markers p63, β1 integrin and keratin 19 (K19) expression whose difference was analyzed by statistic in the skin of nude mice and wild-type mice.Results1. Hematoxylin-Eosin staining:At low magnification, nude mice epidermis where none hair shaft protruded whose surface was smooth was thicker than that of wild-type mice whose hair shafts protruded from epidermis. At high magnification, the epidermis of nude mice consisted of three to four layers of epithelial cells, whereas wild-type mice epidermis consisted of 1 to 2 layers of epithelial cells. On the other hand, there were also morphological differences in stratum basale cells and upper stratum basale cells between nude mice and wild-type mice. The stratum basale cells of nude mice were cuboidal or columnar, and had hyperchromatic, oval, centered nuclei while the basal layer cells of wild type mice were cuboidal, and had rounded nuclei. Stratum granulosum could be easily observed in the epidemis of nude mice, whereas there was no stratum granulosum can be found in epidermis of wild-type mice. The sebaceous glands of the adult nude mice were less devoloped than that of wild-type mice.2. Immunofluorescence staining:p63 was expressed in the nucleus of follicles and stratum basale cells of nude mice and wild-type mice, while β1 integrin was expressed in the hair follicles and stratum granulosum cells of nude mice, and in the hair follicle of wild-type mice. K19 was expressed in the hair follicles and stratum basale cells of nude mice and wild type mice.3. Immunohistochemical staining:The MOD value was calculated by Image analysis software (Image-Pro plus 6.0) with statistical analysis. It could be determined that the MOD value difference of p63, β1 integrin and K19 was significant (P< 0.01) between nude mice and wild-type mice. The quantity of p63, β1 integrin and K19 expression of nude mice skin was less than that of wild-type mice.ConclusionsThere were differences in the epidermis, dermis and skin appendages between adult nude mice and the wild-type mice. The epidermis of nude mice was thicker than that of wild-type mice. And sebaceous gland of nude mice is less developed than that of wild-type mice. There was no distribution difference of p63 and K19 expression between nude mice and wild-type mice skin, while the difference of β1 integrin expression distribution between two types of mice could be detected. β1 integrin expression distributed in the hair follicles and stratum granulosum cells of nude mice while β1 integrin expression of wild-type mice distributed only in the hair follicle. There was also difference in quantity of p63、K19 and β1 integrin expression. The quantity of three epithelial stem cell markers expression of nude mice was lower than that of wild-type mice, and the difference was significant.In conclusion, there were differences in structure of epidermis, dermis and skin appendages and epithelial stem cell markers expression which can be regarded as references that distinguish the type of skin between nude mice and wild-type mice... |
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