Effects of lidocaine on peripheral blood mononuclear cells from patients with atopic dermatitis stimulated by the Staphylococcus aureus exotoxin TSST-1

Abstract

Objective To investigate the effect of lidocaine on Staphylococcus aureus exotoxin-stimulated peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD) . Methods Peripheral blood samples were collected from 6 patients with AD, and PBMCs were isolated by a routine method. Then, the PBMCs were stimulated by the Staphylococcus aureus exotoxin toxic shock syndrome toxin-1 (TSST-1) in the absence or presence of lidocaine at varying concentrations. The 3H-TdR incorporation method was performed to detect the proliferation of monocytes, and enzyme-linked immunosorbent assay (ELISA) to quantify the levels of T helper type 1 (Th1) and Th2 cytokines released by PBMCs. Human HaCaT keratinocytes were co-cultured with lidocaine- and TSST-1-stimulated PBMCs from patients with AD for 72 hours, then, Western blot was conducted to examine the expression of filaggrin protein in HaCaT cells. Results TSST-1 (100 μg/L) significantly enhanced the proliferation of PBMCs from patients with AD (stimulation index = 75 ± 2.12, P < 0.05) , as well as the release of tumor necrosis factor-α (TNF-α) , interferon (IFN) -γ, interleukin (IL) -2, IL-12, IL-4, IL-5 and IL-13 by the PBMCs (all P < 0.05) . Compared with the blank control group, 100 μmol/L lidocaine significantly inhibited the TSST-1-stimulated proliferation of PBMCs from patients with AD (stimulation index = 58 ± 3.14, P < 0.05) , as well as the release of IL-4, IL-5, IL-13, TNF-α and IFN-γ by the stimulated PBMCs (all P < 0.05) . Western blot showed that 100 μmol/L lidocaine significantly blocked the down-regulation of filaggrin expression in HaCaT cells (P < 0.01) . Conclusion Lidocaine has a significant inhibitory effect on the activation of TSST-1-stimulated PBMCs from patients with AD. Key words: Atopic dermatitis; Staphylococcus aureus; Exotoxins; Lidocaine; Monocytes