RESUMO
OBJECTIVE: To determine whether gene expression of collagen type I and interleukin-1 beta (IL-1beta) is altered in patients with atrial fibrillation (AF). METHODS: Right atrial tissue samples were taken from 75 patients with rheumatic heart disease who underwent heart valve replacement surgery. 34 patients had no history of AF, 11 patients had paroxysmal AF and 30 patients had persistent AF. The mRNA content of collagen type I and IL-1beta was measured with semi-quantitative RT-PCR. RESULTS: The mRNA content of collagen type I was significantly increased in the persistent AF group (P < 0.001) and increased in the paroxysmal AF group (P < 0.05) as compared with that in the sinus rhythm group. The mRNA content of IL-1beta was up-regulated in the persistent AF group (P < 0.05), but the trend of increase did not reach statistical significance in the paroxysmal AF group (P > 0.05). The mRNA content of IL-1beta was significantly correlated with the mRNA content of collagen type I (r = 0.295, P = 0.011), left atrial dimension (r = 0.385, P = 0.001) and AF duration (r = 0.326, P = 0.004). CONCLUSION: The upregulation of IL-1beta gene expression in atrium may contribute to the atrial fibrosis during AF through influencing collagen metabolism.