Figure 4
Culture characteristics of melanocytes and melanin production. (A) The cumulative population doubling versus duration of culture demonstrates a relatively linear increasing population doubling rate with the progression of time (left). Limbal melanocytes (LM) from passages 2 (P2), P10, P20, and P30 showing similar proliferative potential (right). Data are shown as mean ± SEM (n = 5). (B) LMs were cultured in the presence or absence of 1 mM L-DOPA for 24 h. l-DOPA treated cells produced melanin, causing light brown coloring of the culture medium, as can be observed macroscopically (i). Phase-contrast images also show the darkening of the cells 24 h after treatment with l-DOPA compared with 0 h (ii). l-DOPA stimulation significantly increased the intracellular melanin concentration (twofold), whereas the melanin concentration in the medium was increased to sixfold compared to unstimulated condition (iii). Data are expressed as means ± SEM (n = 6) *p < 0.05; **p < 0.005; Mann–Whitney U test.
