Abstract:

Objective To study the survival and melanogenic potential of human melanocytes reversibly immortalized via SV40T antigen gene and Cre/loxP system in Guinea pigs. Methods The supernatants of retrovirus vector Cre-ERT2 were used to infect melanocytes which had been successfully transfected by SV40TAg gene （MCT）, then the expression of Cre recombinase was induced with tamoxifen in infected cells; subsequently, the surviving cells, which were named as MCTC, were subjected to expansion culture. Guinea pigs were utilized to establish animal models of vitiligo, then MCTC and primary melanocytes were transplanted respectively into the animal models. The repigmentation at the transplanted area was observed with naked eyes successively until 3 months after the transplantation when tissue samples were obtained from implanted area and nonimplanted area of guinea pigs and subjected to Masson-Fontana silver stain and Hematoxylin-eosin stain for the analysis of melanocyte distribution and melanin deposition in epidermis. Results Repigmentation started 4 weeks after the transplantation, and dark or brown patches, which ranged in size from 0.5 to 1 cm, were observed in the implanted area 3 months after the transplantation. The repigmentation rate was of no significant difference between pigs transplanted with MCTC and those with primary melanocytes （82.5% vs 76.7%, P > 0.05）. Pathological examination revealed melanin deposition in the basal layer of epidermis and some hair follicles in transplanted area. Conclusions SV40T antigen gene combined with Cre/loxP site-specific recombinase system can induce the reversible immortalization of human melanocytes, and the immortalized melanocytes have a favorable profile of biological safety and similarity in survival rate and melanogenic potential to primary melanocytes.

Key words: Cre/loxP system