Isolation, purification and cultivation of conjunctival melanocytes

The purpose of the present study was to develop methods for isolation, purification and cultivation of human conjunctival melanocytes. Conjunctiva excised from donor eyes or corneal rims was subjected with various enzyme digestion methods or by the enzyme-microdissection method. Cells were cultured with F12 medium supplemented by fetal bovine serum, basic fibroblast growth factor, isobutylmethylxanthine and cholera toxin. Contaminant cells were eliminated by a selective cytotoxic agent, geneticin. Both trypsin digestion and dispase-microdissection methods provided pure conjunctival melanocyte cultures with high cell yields, good viability and rapid growth rate. Melanocytes isolated with dispase-microdissection method showed better viability and growth capacity. Cells grew well, could be passaged for 5-10 generations and divided 20 times in vitro. They maintained a constant melanin content per cell and produced measurable amounts of melanin in vitro. Melanogenesis correlated with the degree of pigmentation of the eyes (iris color). This method provides a valuable source of large numbers of human conjunctival melanocytes, which can be used to study their biological behavior, to compare with the epidermal and uveal melanocytes; and to compare them to their malignant counterparts in the exploration of the pathogenesis of conjunctival melanoma.