Abstract: Abstract Objective：To observe the effect of probucol on myocardial injury, inflammation and endothelial function in patients with unstable angina pectoris (UAP) underwent percutaneous coronary intervention (PCI), and investigate the probable mechanism of probucol. Methods：107 patients with UAP randomly divided into probucol group (52 cases) and control group (55 cases). Standard medical therapies were given in all 107 patients. The CK-MB, cardiac troponin I (cTnI), high-sensitivity C-reactive protein (hs-CRP) and nitric oxide (NO) were measured in all enrolled subjects before PCI right time and at 6:00 in the next day morning after PCI. Results：The levels of hs-CRP, CK-MB and cTnI were elevated and the level of NO was decreaed significantly after PCI in control group (P<0.05). The levels of CK-MB and cTnI were elevated significantly (P<0.05), but there were no significant changes in the increased level of hs-CRP (P>0.05) and the decreased level of NO (P>0.05) after PCI in the probucol group. However, the ascended value of hs-CRP and the descended value of NO in the probucol group were significantly lower than those in control group (P<0.05), the ascended values of CK-MB and cTnI in the probucol group were higher than those in control group (P>0.05). Conclusions：Probucol therapy in more than 24 hours before PCI can significantly reduce the inflammatory reaction and improve endothelial function and prognosis in patients with UAP, but there is no evident function on reducing myocardial injury.

Key words: probucol, unstable angina pectoris, percutaneous coronary intervention, myocardial injure, inflammation, endothelial function