[Expression of SIRT1 in right auricle tissues and the relationship with oxidative stress in patients with atrial fibrillation].

Aim: To observe the expression of mammalian sirtuin 1 (SIRT1) in right auricle tissues in patients presenting with atrial fibrillation (AF) and make clear the relationship between SIRT1 expression and oxidative stress.

Methods: A total of 38 patients with rheumatic heart disease were divided into 2 groups: AF group (AF lasted more than 6 months, n=25) and SR (sinus rhythm) group (n=13). The expression of SIRT1 in right auricle tissues harvested during heart operations was detected by immunohistochemistry. Oxidative stress was estimated by the amounts of malondialdehyde (MDA) and metallothionein (MT) and the activity of superoxide dismutase (SOD) which were detected using thiobarbituric acid reaction (TBA), enzyme-linked immunosorbent assay (ELISA) and xanthine oxidase assay, respectively.

Results: Compared with the SR group, the expression of SIRT1 protein in the atrium significantly increased in AF group [P<0.05, (45.8±4.03)% vs (19.7±2.54)%]. In AF group, MDA was (7.24±1.05) nmol/mg, SOD (1034.25±84.32) U/mg and MT (7.21±1.46) μg/g, all being significantly higher than those in SR group[P<0.05, MDA: (3.01±0.47) nmol/mg; SOD: (723.63±65.23) U/mg; MT: (4.31±1.23) μg/g]. Spearman correlation indicated that the expression of SIRT1 had a significantly negative correlation with the amounts of MDA and MT and the activity of SOD (P<0.05, r=-0.447, -0.521, -0.394, respectively).

Conclusion: The expression of SIRT1 increased in patients with AF. SIRT1 maybe effects the AF by means of inhibiting the process of oxidative stress.