Abstract
Abstract: :
Purpose:To study the effect of an inflammatory mediator-tumor necrosis factor-alpha (TNF-alpha) on the growth and melanogenesis of cultured uveal melanocytes (UM). Methods:Human UM were isolated and cultured from donor eyes as previously reported. Early passages of UM were plated into multi-well plates and cultured with complete medium (F12 medium with 20 ng/ml bFGF, 1 mM IBMX, 10 ng/ml cholera toxin and 10% serum). TNF-alpha was added to the culture medium at various concentrations. Each group was performed in triplicate. Cells cultured with the complete medium without TNF-alpha were used as controls. After 6 days, cells were detached and counted. Melanin content was measured spectrophotometrically. Results:UM cultured with complete medium grew well and produced melanin in vitro. TNF-alpha inhibited the growth and melanogenesis in a dose-dependent manner from 1 ng/ml to 100 ng/ml. The cell number of TNF-alpha treated group was 75% (1 ng/ml) to 30% (100 ng/ml) of the controls. Conclusion: The UM are very stable in vivo and do not respond in most pathologic conditions, such as injury and inflammation. It has been reported that some inflammatory mediators (e.g. Prostaglandin E) stimulate the growth and melanogenesis of UM in vitro. The growth inhibiting effect of TNF-alpha may counteract the stimulating effect of PGE or other stimulating mediators to maintain the stability observed in vivo of UM during inflammatory insults.
Keywords: 463 melanocytes • 380 cytokines/chemokines • 345 choroid