OBJECTIVETo study the effect and mechanism of arsenic trioxide (As2O3) on apoptosis of pulmonary eosinophiles (PE) in asthmatic guinea-pigs.

METHODSThirty guinea-pigs were divided into 3 groups at random, the control group, the asthmatic group and the As2O3 group. The dosage of As2O3 used was 2 mg/kg. The apoptotic PE were labelled by TdT-mediated dUTP nick end labelling technique, and the PE infiltration and apoptosis were detected quantitatively using computerized image analysis technique.

RESULTSIn the control group, the amount of infiltrating PE was 4.4 +/- 2.5 cells/HP and the PE apoptotic index (AI) was 0.42 +/- 0.08%. In the asthmatic group, the amount increased (P < 0.01) and AI decreased significantly (P < 0.01). After the asthmatic animals had been treated with As2O3, the two parameters changed reversedly significantly (P < 0.01), and there was a significantly negative correlation between them (r = -0.949, P < 0.01).

CONCLUSIONThe PE apoptosis abnormality is one of the important mechanisms that cause bronchial asthma, As2O3 could alleviate the airway inflammation through promoting PE apoptosis and lower PE infiltration. Low dose of As2O3 is proved to be effective with relative safety, it also has potential value in treating asthma.