In vitro arsenic trioxide induces apoptosis in T cells of asthmatic patients by a Bcl-2 related mechanism / 药学学报

ABSTRACT

This study examined the effects of arsenic trioxide on apoptosis and interleukin4 release in T cells of asthmatic patients in vitro and investigated the role of Bcl2 in the active mechanism. Tcells were isolated from asthmatic patients (n=21) and healthy controls (n=20), and then treated with arsenic trioxide and dexamethasone. Cell apoptosis was measured using fluorescence microscopy, flow cytometry and a cytochrome c ELISA kit. Interleukin4 levels in the serum and in supernatants from T cells were quantified by ELISA. Flow cytometric analysis and immunofluorescence studies were performed to determine Bcl 2 expression. Tcells of the asthmatic patients (I.e. without treatment) exhibited decelerated spontaneous apoptosis after 24 h incubation in vitro when compared to T cells of the healthy controls. With dexamethasone treatment, an increase in apoptosis of Tcells was not significantly different between both groups, irrespective of the method used. Arsenic trioxide treatment, however, significantly increased the apoptosis of T cells of the asthmatic group and showed a slight effect on the control group. In asthmatic patients, elevated levels of interleukin 4 and upregulated Bcl 2 expression were detected. Moreover, in vitro, T cells of asthmatic patients spontaneously released more interleukin4 and exhibited more Bcl 2 expression than T cells from the control group. Arsenic trioxide treatment significantly decreased interleukin4 release and downregulated Bcl 2 expression in asthmatic patients, while it only slightly affected healthy controls. Dexamethasone treatment decreased interleukin4 release in both groups examined. It did not significantly influence Bcl2 expression. These results suggest that arsenic trioxide induces T cell apoptosis and decreases interleukin4 release in T cells of asthmatic patients in vitro and that downregulation of Bcl2 expression may be an important mechanism.