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

<b>Background/Objectives</b>: We investigated whether palmitic acid (PA) induced the expression of inflammatory cytokines and was involved in pyroptosis in a human dental pulp cell line. <b>Methods</b>: Human dental pulp cells cultured in Minimum Essential Medium Alpha (αMEM) were treated with 1 µg/mL LPS and/or PA (100, 300 and 500 µM). As a control, αMEM 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 <i>IL-1β</i>, <i>IL-6</i>, <i>TNF-α</i>, <i>caspase-4</i> and <i>gasdermin d</i> were detected by quantitative RT-PCR (qPCR). <b>Results</b>: The WST-1 assay showed that cell viability decreased by 36% at 300 µM and 47% at 500 µM PA compared to the control (<i>p</i> < 0.05). Cell morphology revealed slight shrinkage in 100, 300 and 500 µM PA groups. RNA expression of <i>IL-1β</i> and <i>IL-6</i> in the PA groups was significantly higher than that in the control groups (<i>p</i> < 0.05), while RNA expression of <i>TNF-α</i> in the PA group was the same as that of control group. The mRNA expression of <i>caspase-4</i> and <i>gasdermin d</i> in PA groups was significantly higher than that in control group (<i>p</i> < 0.05). Likewise, the concentration of IL-1β and IL-6 was significantly higher in both LPS and PA groups than that in the LPS or PA groups (<i>p</i> < 0.05). <b>Conclusions</b>: 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.