Objective    To investigate the role of TGF-β1 in the atrial myocardial fibrosis in the patient with rheumatic heart disease(RHD).     Methods    Of 38 RHD patients

8 were with sinus rhythm

10 with paroxysm atrial fibrillation (pAF) and 20 with chronic AF(cAF) (≥6 months). The right atrial muscle specimens were obtained during the operation on mitral valve replacement. The collagen content and distribution of myocardium specimens were obtained by hydroxyproline detection and Masson staining. Expression and distribution of TGF-β1 were examined by immunohistochemical staining. The mRNA content of TGF-β1 was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Proteins of TGF-β1 was measured by Western blotting.     Results    RHD atrial myocardium had high content of collagen. TGF-β1 was distributed mainly in myocardium cells. Both of the collagen content and mRNA or protein expression of TGF-β1 in pAF group (P0.05) and cAF group (P0.01) was stronger than that in sinus rhythm group; cAF group was stronger than that in pAF group (P0.05). The mRNA and protein expression of TGF-β1 in RHD was increased and correlated positively with the content of myocardial collagen.     Conclusion    The mRNA and protein expression of TGF-β1 in human atria may have correlation with the initiation or maintenance of AF

and contribute for the development of atrial fibrosis in patients with RHD

which produces a structural basis for AF.