Palmitic Acid Induces Inflammatory Environment and Is Involved in Pyroptosis in a Human Dental Pulp Cell Line

Abstract

Background/Objectives: We investigated whether palmitic acid (PA) induced the expression of inflammatory cytokines and was involved in pyroptosis in a human dental pulp cell line. Methods: Human dental pulp cells cultured in Minimum Essential Medium Alpha (alpha MEM) were treated with 1 mu g/mL LPS and/or PA (100, 300 and 500 mu M). As a control, alpha MEM was added in the culture medium. The WST-1 assay was performed to assess cell proliferation, and morphological changes in cells were examined. RNA expression of IL-1 beta, IL-6, TNF-alpha, caspase-4 and gasdermin d were detected by quantitative RT-PCR (qPCR). Results: The WST-1 assay showed that cell viability decreased by 36% at 300 mu M and 47% at 500 mu M PA compared to the control (p < 0.05). Cell morphology revealed slight shrinkage in 100, 300 and 500 <mu>M PA groups. RNA expression of IL-1 beta and IL-6 in the PA groups was significantly higher than that in the control groups (p < 0.05), while RNA expression of TNF-alpha in the PA group was the same as that of control group. The mRNA expression of caspase-4 and gasdermin d in PA groups was significantly higher than that in control group (p < 0.05). Likewise, the concentration of IL-1 beta and IL-6 was significantly higher in both LPS and PA groups than that in the LPS or PA groups (p < 0.05). Conclusions: The results of this study suggest that PA induces the expression of inflammatory cytokines and is involved in pyroptosis in a human dental pulp cell line.