Aim This study was to investigate the aspect ofsmooth muscle cell (SMC) apoptosis and inducible ni-tric oxide synthetase (iNOS) gene expression in theearly periods of rabbit aorta injury model.Metkods The endothelium of rabbit abdominalaorta was injuried by a ballon angioplasty catheter,the presence of apoptotic SMC was demonstrated byterminal deoxynucleotidyl transferase-mediated dUTPnick end labeling (TUNEL). The expression of iNOSmRNA was eveluated by reverse transcription-poly-merase chain reaction (RT-PCR) methods.Results TUNEL analysis showed that the mediaSMC underwent apoptosis after injury. The index ofapoptotic SMC was 6% at 0 hour. It was significantlyincreased t0 15% at 8 hours, and reach a maxium(50%) at 24 hours, and maintained a high level at 3days (32% ) and 5 days (20% ). No significant incre-ment of apoptotic cells was observed in adventitia inthe early periods of artery injury. The expression of i-NOS gene mRNA in artery was significantly increasedafter injury, and was parallel with cell apoptotic in-dex.Couclusion Vascular media SMC of rabbit abdomi-nal aorta underwent apoptotic cell death in the earlyperiods of injury caused by ballon catheter. The in-duction of apoptosis coincided with iNOS mRNA ex-pression.