Expression Pattern And Possible Role Of COX-2 In Normal Pilosebaceous Unit

Pilosebaceous Unit(PSU) as a basic structure unit takes part in the skin construction, composed of cycling hair follicle,renewing epidermis and constantly releasing sebaceous gland. Previous data demonstrated that PSU kept continous self-renewal and the intricate balance between cell proliferation and differentiation throughout life, so that it could provide the larggest protective external barrier and functional maintenance during life. A great number of molecules involved in this process. Cyclooxygense(COX)-2 which is a key limited enzyme in prostaglandins synthesis usually catalyze the productionof several PGs that control physiological functions. COX-2 is not expressed constitutively in most normal tissues but can be rapidly induced.. Epidemiologcial and experimental research showed that the upregualtion of COX-2 is definitely correlated with a series of epithelial tumors. COX-2 transgenic mice also displayed the abnormal phenotype such as sebaceous gland hyperplasia and delayed hair follicle development. These clues highlight that COX-2 may play an important role in cell diffenentiation (whether normal differentiation or neoplasia). Because the two specific phenotypes both epithlial tumors and sebaceous gland hyperplasi are obvious markers of cell differentiation. On the other hand, several papers reported that COX-2 expressed constitutively in normal brain and kidney. Diverse results mentioned investigators that COX-2's function may be multiple and is not restricted only in epithelial neoplasm and inflammatory reactions.Whether normal Pilosebaceous Unit expressed COX-2 is unclear. What's the influence on hair follicle cycle and hair follicle stem cells if COX-2's expression is positive ? Similar investigation has not been reported.In our stydy, we explored the expression pattern of COX-2 in normal rat Pilosebaceous Unit and hair follicle cycle adopting immunochemistry and RT-PCR methods. Moreover, COX-2 overexpression in primary hair follicle stem cell has been manipulated in vitro by gene transfection and observed its influence on cell differentiation of hair follicle stem cells.