Effects of total glucosides of paeony on cell proliferation of and expression of vascular endothelial growth factor (VEGF) and interleukin (IL)-23 in human HaCaT keratinocytes / 中华皮肤科杂志

ABSTRACT

Objective To evaluate the effects of total glucosides of paeony (TCP) on cell proliferation of and expression of VECF and IL-23 in human HaCaT keratinocytes and their potential mechanisms. Methods MTT assay was performed to detect the cell proliferation of HaCaT cells incubated with various concentrations (0.5 to 312.5 mg/L) of TGP. HaCaT cells were classified into 8 groups, control group without any treatment, TGP groups treated with 6 different concentrations of TGP, SB203580 group treated with TGP of 125 mg/L after 2-hour pretreatment with SB203580 of 10 μmol/L After additional culture, reverse transcription (RT)- PCR and enzyme linked immunosorbent assay (ELISA) were conducted to determine the expression levels of VEGF and IL-23 mRNA and protein, Western blot to test the phosphorylation of p38 mitogen-activated protein kinase (MAPK) in these cells. Results The proliferation of HaCaT cells was promoted by TGP of low concentrations (0.5 and 2.5 mg/L), but inhibited by TGP of equal to or more than 12.5 mg/L, and peaked at the concentration of 125 mg/L. TGP of 0.5 and 2.5 mg/L enhanced the mRNA and protein expressions of VEGF and IL-23, while TGP of 12.5 to 125 mg/L suppressed the expression of VEGF mRNA and protein, and TGP of 62.5 to 125 mg/L downregulated the expression of IL-23 mRNA and protein. The phosphorylation of p38 protein kinase in HaCaT cells was induced by TGP of 125 mg/L in a time-dependant manner. Concretely, the level of phosphorylated p38 kinase in HaCaT cells was 0.3314 ± 0.0245 (peak) at 5 minutes, decreased to 0.2173 ± 0.0189 at 10 minutes (still statistically higher than untreated HaCaT cells) and 0.1664 ± 0.0201 at 30 minutes after treatment with TGP of 125 mg/L. SB203580 attenuated the effect of TGP on p38 phosphorylation, and the level of phosphorylated p38 kinase was 0.1529 ±0.0147 in HaCaT cells pretreated with SB203580 prior to the treatment with TGP. Conclusion TGP can inhibit the cell proliferation of and expressions of VEGF and IL-23 mRNA and protein in HaCaT cells, likely mediated by the p38 MAPK signaling pathway.