Abstract:

Objective To investigate the relationship between apoptosis in epidermal keratinocytes and efficacy of epidermal grafting. Methods Epidermal specimens were obtained from donor sites and depigmented area of 44 patients with vitiligo receiving epidermal grafting. The apoptosis in keratinocytes was determined by terminal deoxynucleotidyl transferase end-labeling （TUNEL） assay, and the expressions of Caspase 3, 8, 9 as well as bcl-2 and P53 were evaluated by immunohistochemistry. Results As TUNEL assay showed, the number of apoptotic keratinocytes in epidermis from depigmented area differed significantly from that from donor sites. The expressions of Caspase 3, 8 and 9 were mainly located in the membrane and cytoplasm of keratinocytes, and positive keratinocytes were predominately distributed in the middle and lower layer of the epidermis. Of the 44 patients, 19, 15 and 16 were positive for the expressions of Caspase 3, 8 and 9 in the depigmented epidermis, respectively, and 9, 5 and 4 for those in the donor epidermis, respectively. P53 was expressed in neither donor epidermis nor depigmented epidermis, while Bcl-2 was weakly positive in donor epidermis and negative in depigmented epidermis. The number of apoptotic keratinocytes was higher in donor epidermis from patients failing to respond to the transplantation than in that from patients successfully treated by transplantation （15.83 ± 2.69 vs. 9.24 ± 1.80, t = 10.96, P < 0.01）. Conclusions There is an obvious apoptosis in keratinocytes from depigmented epidermis of patients with vitiligo, together with an increase in the expression of Caspase 3, 8 and 9. The apoptosis in keratinocytes may be related to the efficacy of epidermal transplantation.

Key words: vitiligo, Keratinocytes, Apoptosis, Transplantation