Effect of heat treatment on the viability of cultured normal human melanocytes / 中华皮肤科杂志

ABSTRACT

Objective To investigate the effect of heat treatment on the proliferation of, melanin synthesis and tyrosinase activity in cultured normal human melanocytes. Methods Normal human foreskin tissue was obtained by sterile circumcision and melanocytes were harvested by using methods for epidermal cell culture. Basic fibroblast growth factor (bFGF) was utilized as the primary mitogen to establish the culture system of normal human epidermal melanocytes. Masson-Fontana staining was proformed to identify melanocytes.Third-passage melanocytes were treated with hyperthermia at various temperatures (39 ℃, 41 ℃, 42 ℃, 43 ℃ and 45℃) for 1 hour a day for consecutive 3 days followed by the measurement of cell viability with MTT assay. The hyperthermia at optimized temperature was used to treat fourth-passage melanocytes for 1 hour a day for consecutive 3 days; subsequently, the tyrosinase activity were detected with L-Dopa as the substrate, and melanin content was determined in heat-treated and untreated (control) melanocytes. Results The hyperthermia at 42 ℃ exhibited the strongest promotive effect on the proliferation of melanocytes among these 5 hyperthermia conditions. After treatment with hyperthermia at 42 ℃ for 1 hour a day for consecutive 3 days, melanocytes showed an increment in tyrosinase activity by 36.4% and melanin synthesis by 78% compared with the untreated melanocytes (both P＜0.05). Conclusions Heat treatment can enhance the proliferation of cultured human melanocytes, promote their melanin synthesis and tyrosinase activity.