The Influence Of The Epidermal Differentiation On Mouse Tail Scale By Application Of Topical Treatment Of Retinoid

Backgrouds:Psoriasis is a common,chronic,recurrent, inflammatory disease of the skin characterized by round,circumscribed, erythematous, dry, scaling plaques of various sizes, covered by grayish white or silver white, imbricated, and lamellar scales. The cause of psoriasis is still unknown, it is considered that the psoriasis is a disease of multifactorial inheritance caused by many kinds of factors such as genetic, environmental factors, etc.There are not so many kinds of drugs to treat the psoriasis effectively now. The pathogenetic key point of psoriasis is the hyperkeratosis and parakeratosis of the malpighian cell. Normally, the keratinocytes of the horny layer of epidermis retain the cell nucleus in mouse tail scales, but the cells lack of the granular layers. For these features, the animal model can stimulate the psoriasis. How to improve these phenomenons is the main path to treat the psoriasis.The drugs of retinoid are a kind of compounds which are similar with vitamin A ,they have extensive biological effect,and the major effect is to affect the metabolism of the epithelial tissue ,promote the epithelial growth and differentiation,dissolve the horny,then participate to regulate the hyperplasy,differentiation,apopotosis of the epidermal cell, in order to induce the hyperplasy of epidermis ,then increase the granular layers and the prickle cell layers.The experiment use the psoriasis animal model to evaluate the influence of the granular layers of the mouse tail scales, by five kinds of the topical treatment of retinoid. If the drug can induce the granular layers, that is to say,it may change the process of cornification from parakeratosis to nomal, the drug could have thetherapeutical effect to the disease.Objective:To observe the influence of the epidermal differentiation by topical using the five kinds of retinoids .Materials and Methods:We use five kinds of retinoids by painting to the mouse tail,which are Viaminate and Vitamin E Cream, 0.1% Tretinoin Cream,0.05%Isotretinoin Gel,0.1%Adapalene Gel, 0.1%Tazarotene Cream, by group,daily, for 14 days.Then we execute the animals the day after the last painting,cut off the mouse tail at 1cm distance between the root,avoid the damage,cutdown the skin, decoherence the cartilage,get the rectangle free skin graft about 1cm2 ,paste them to the filter paper,throw them to the 10%formal immediately to fix them ,then routine anhydration,paraffin imbedding,cut sheets,HE dyeing,and then observe the histological changes by light microscope.Count the number of the granular layers in 100 scales,then carry out the data by statistical treatment .Results:We don't see the severe topical skin stimulus response by naked eye .We observe the results by histology, the results show that the epidermis and corneous layers of the experiment groups become much thicker than control group's .There appeared the continuous and thickening granular layer, the thicker ,anachromasis cells,clear cell boundary, the caryon, nucleoli,and the increased more tightly basilar membrane.The data show that the experiment groups have the effect of promoting the granular layers via the control group's,and the discrepancy are significantly,(p<0.05). And tazarotene group show the most significantly effect,the number of the granular cells increased from 7.0±1.07 to 69.5±12.60,the discrepancy is extremely notable(t=13.975,p<0.01),the isotretinoin group's increased to 62.25±9.79,the discrepancy is extremely notable(t=15.861,p<0.05),but the discrepancy between them is not obvious.The discrepancy between Viaminate and Vitamin E and adapalene group is not obvious, too ,the discrepancy between other groups is obvious.Conclusions:The mouse tail scale model have the value of screening the topicalusing for treating the psoriasis. The five kinds of drugs also have the significant effect of promoting the granular layers,and the discrepancy is notable .Among the groups,the effect of Viaminate-Vitamin E group and Adapalene group are weaker than other groups;and the effect of Tazatotene group and Isotretinoin group are much stronger than others .And we don't see the severe topical skin stimulus response during the experiment process .