Effects Of Glucocorticoids On The Synthesis Of Melanin In A375 Human Melanoma Cells

Objective: The aim of our research is to study the mechanism of glucocorticoids in treating vitiligo by examining the effects on the growth of cells, tyrosinase activity and melanogenesis after treatment of A375 human melanoma cells. Cells were treated with various doses of hydrocortisone, prednisolone acetate, and dexamethasone sodium phosphate .Methods: A375 human melanoma cells were treated with different concentration of hydrocortisone, prednisolone acetate, and dexamethasone sodium phosphate. To observe the growth of A375 human melanoma cells by MTT, the changes of tyrosinase activity were detected by dioxypenylalanine oxidation, the content of melanin was detected by spallation of NaOH.Results: 1. When the concentration of hydrocortisone was between 10^-6M and 10^-5M, it showed an increasing tendency of the amount of A375 human melanoma cells with the concentration of hydrocortisone raised,compared with control. While prednisolone acetate and dexamethasone sodium phosphate did not influence cell proliferation between the concentrations from 10^-9M to 10^-5M, compared with control.2. When the concentration of dexamethasone sodium phosphate was between 10-8M and 10^-5M,it showed an increasing tendency of tyrosinase activity,while hydrocortisone and prednisolone acetate increased the tyrosinase activity at 10^-6M and 10^-5M. Compared with the other groups,when the concentration of dexamethasone sodium phosphate reached to 10^-5M, the tyrosinase activity was the most.3. With concentrations of dexamethasone sodium phosphatethe changing between 10-8 M and 10^-5 M, it showed an increasing tendency of melanogenesis, while hydrocortisone and prednisolone acetate increased melanogenesis at 10^-6 M and 10^-5 M concentrations. Compared with the other groups, when the concentration of dexamethasone sodium phosphate reached to 10^-5 M, the melanogenesis was the most. Conclusion: hydrocortisone of certain concentration may promote the growth of A375 human melanoma cells. Hydrocortisone, prednisolone acetate and dexamethasone sodium phosphate of certain concentration may increase the activity of tyrosinase, and enhance the melanin content. These results provide experimental evidence to treat vitiligo patients with glucocorticoids.