Abstract: 【Abstract】 Objective To evaluate the effect of water-soluble components of atmospheric fine particulate matter PM2.5 on proliferation, migration, tyrosinase activity and melanin content of a human melanocyte line PIG1. Methods PM2.5 was collected during haze weather in heating seasons, and processed into suspensions. PIG1 melanocytes were cultured and divided into 5 experimental groups and 1 control group. PIG1 melanocytes in the 5 experimental groups were treated with 10, 20, 50, 100 and 200 mg/L PM2.5 suspensions respectively for 48 hours, while cells in the control group were not treated with PM2.5 suspensions. In cell migration assay, there was only 1 experimental group treated with 10 mg/L PM2.5 suspensions. After treatment, methyl thiazol tetrazolium （MTT） assay, micropore filtration assay, DOPA oxidase assay and NaOH lysis method were performed to determine the cell proliferation rate, migration rate, tyrosinase activity and melanin content respectively. Statistical analysis was carried out by using t test for comparison of means of two samples, one-way analysis of variance for means of multiple samples, Student-Newman-Keuls （SNK）-q test for multiple comparisons, and linear correlation analysis for analysis of correlations. Results Compared with the control group （［100 ± 1.41］%）, the proliferation rate of PIG1 cells significantly decreased in the 20-, 50-, 100- and 200-mg/L PM2.5 groups （［93.41 ± 2.13］%, ［88.31 ±1.3557］%, ［79.75 ± 1.89］%, ［69.83 ± 2.50］% respectively, all P < 0.05）. Linear correlation analysis showed that the proliferation rate and tyrosinase activity of PIG1 cells decreased with the increase in PM2.5 concentrations （r = -0.98, -0.93, respectively, both P < 0.01）. After the treatment with 10 mg/L PM2.5, the migration rate of PIG1 cells significantly decreased （66.23% ± 1.11%） compared with the control group （［76.86 ± 1.81］%, t = 7.55, P < 0.01）. With the increase in PM2.5 concentrations （50 - 200 mg/L）, the melanin content of PIG1 cells gradually decreased （r = -0.97, P < 0.01）. Conclusion Atmospheric fine particulate matter PM2.5 can affect the normal functions of melanocytes by inhibiting their proliferation and migration, and reducing their tyrosinase activity and melanin content.

Key words: Melanocytes, Particulate matter, Cell proliferation, Melanins, Cell migration assays, PM2.5