Propofol inhibits T-helper cell type-2 differentiation by inducing apoptosis via activating gamma-aminobutyric acid receptor.

BACKGROUND: Propofol has been shown to attenuate airway hyperresponsiveness in asthma patients. Our previous study showed that it may alleviate lung inflammation in a mouse model of asthma. Given the critical role of T-helper cell type-2 (Th2) differentiation in asthma pathology and the immunomodulatory role of the gamma-aminobutyric acid type A (GABAA ) receptor, we hypothesized that propofol could alleviate asthma inflammation by inhibiting Th2 cell differentiation via the GABA receptor.

METHODS: For in vivo testing, chicken ovalbumin-sensitized and challenged asthmatic mice were used to determine the effect of propofol on Th2-type asthma inflammation. For in vitro testing, Th2-type cytokines as well as the cell proliferation and apoptosis were measured to assess the effects of propofol on Th2 cell differentiation and determine the underlying mechanisms.

RESULTS: We found that propofol significantly decreased inflammatory cell counts and interleukin-4 and inflammation score in vivo. Propofol, but not intralipid, significantly reduced the Th2-type cytokine interleukin-5 secretion and caused Th2 cell apoptosis without obvious inhibition of proliferation in vitro. A GABA receptor agonist simulated the effect of propofol, whereas pretreatment with an antagonist reversed this effect.

CONCLUSIONS: This study demonstrates that the antiinflammatory effects of propofol on Th2-type asthma inflammation in mice are mediated by inducing apoptosis without compromising proliferation during Th2 cell differentiation via activation of the GABA receptor.