Abstract: ZHANG Qian, ZHOU Bing-rong, LUO Dan, FANG Xiao-bo, YIN Hui-bin, GUO Ze, WU Wei. Department of Dermatology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China Corresponding author: LUO Dan, Email: daniluo2013@njmu.edu.cn 【Abstract】 Objective To estimate the influence of palmitic acid （PA） on the proliferation of and production of inflammatory mediators by a human keratinocyte line HaCaT. Methods Cultured HaCaT cells were treated with PA of eight concentrations （0 － 200 μmol/L） for 3－24 hours followed by the evaluation of cell proliferation by using the cell counting kit-8. According to the proliferation assay, four concentrations （75, 100, 125, 150 μmol/L） of PA were selected and used to treat HaCaT cells for 24 hours, then, fluorescence-based immunohistochemical staining was performed to observe the nuclear translocation of nuclear factor （NF）-κB p65, enzyme linked immunosorbent assay （ELISA） to determine the level of interleukin （IL）-6 in the supernatant of culture medium, real-time PCR to detect the mRNA expressions of peroxisome proliferator-activated receptor α （PPARα） and IL-6, and Western blot to quantify the protein expressions of PPARα as well as total and nuclear NF-κB p65. Those HaCaT cells receiving no treatment served as the control group. Statistical analysis was carried out by one-factor analysis of variance using the GraphPad Prism 5.0 software. Results The HaCaT cells treated with PA of 50 － 175 μmol/L showed accelerated proliferation compared with the control HaCaT cells （all P < 0.05）. PA from 75 to 150 μmol/L enhanced the nuclear translocation of NF-κB p65, mRNA and protein expressions of PPARα, as well as the mRNA expression and supernatant level of IL-6 in a dose-dependent manner. The relative expression level of nuclear NF-κB p65 protein was 0.4536 ± 0.0173, 0.5184 ± 0.0206, 0.5333 ± 0.0231, 0.6160 ± 0.0297, and the supernatant level of IL-6 was （31.5677 ± 0.2268）, （32.3773 ± 0.4156）, （32.9837 ± 0.0029） and （33.6890 ± 0.0936） ng/L, in HaCaT cells treated with PA of 75, 100, 125 and 150 μmol/L, respectively, compared to 0.3237 ± 0.0114 （all P < 0.01） and （30.4577 ± 0.5131） ng/L （all P < 0.01） in the control HaCaT cells, respectively. Conclusions PA can accelerate the proliferation of HaCaT cells, enhance NF-κB nuclear transfer, PPARα expression and IL-6 secretion in a dose-dependent manner within a certain concentration range, and may exert a promoting role in the activation and expression of some inflammatory factors. 【Key words】 Palmitic acid; Keratinocytes; Cell proliferation; NF-kappa B; Interleukin-6; PPARα

Key words: Palmitic acid