Abstract:

Objective To observe the expression of aryl hydrocarbon receptor （AhR） in human epidermis, hair follicles and sebaceous glands and the activation of AhR by dioxin. Methods Full-thickness skin specimens were obtained from 3 volunteers receiving cosmetic facial surgery. Indirect immunofluorescence and immunohistochemistry were used to detect the expression of AhR in these skin specimens, as well as on cultured human HaCaT keratinocytes and SZ95 sebocytes. Western blot was performed to detect the expressions of AhR protein on HaCaT cells and SZ95 sebocytes after 3-day treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin（TCDD）. Results AhR protein was found to be expressed in human epidermis, hair follicles and sebaceous glands, and the expression was stronger in the stratum spinosum and stratum granulosum than in the basal layer, in the outer and central layer than in the middle layer of sebaceous lobuli, in hair follicle outer root sheath and hair cuticles than in the inner root sheath. There was a high expression of AhR in the nucleus and cytoplasm of HaCaT and SZ95 cells. A significant decrease was observed in the expression of AhR in both HaCaT cells and SZ95 cells after treatment with TCDD for 3 days, hinting that AhR was activated by TCDD. Conclusions AhR is highly expressed in human epidermis, hair follicles and sebaceous glands, and can be activated by TCDD, suggesting that dioxin may induce the abnormal differentiation of epidermis, hair follicles and sebaceous glands via AhR singaling pathway.

Key words: HaCat keratinocytes：SZ95 sebocytes