Correlation Of Calpains With Ultramicrostructure Remodeling And Apoptosis In The Right Atrium Myocytes Of Patients With Rheumatic Chronic Atrial Fibrillation

Objective To approach the content of Calpains, ultramicrostructureremodeling and apoptosis of right atrium myocytes in patients withrheumatic chronic atrial fibrillation(AF), also the relationship betweenthem. Methods 30 patients with rheumatic mitral valve diseases(stenosis, and/or insufficiency), who were underwent mitral valvereplacement, were enrolled in the study and were divided into chronic AFgroup(AF group,n=15) and sinus rhythm group(SR group, n=15). Rightatrial appendages tissue was taken before cardiopulmonary bypass duringoperations. The content of CalpainⅠand CalpainⅡof right atriummyocytes was assayed by Western blot. Ultramicrostructure changes wereobserved by transmission electron microscope(TEM). The apoptosisindex(AI) was measured by TUNEL. The relationships between thesefactors were analyzed. Result Compared with SR group, the AFgroup had a significantly higher content of CalpainⅠ(1.585±0.260 vs1.191±0.099, P＜0.01), but there was no significant difference of CalpainⅡcontent in the two groups (0.845±0.071 vs 0.823±0.078, P=0.22).The AF group had a more serious change of myocyte ultramicrostructure than the SR group, in which we could see a significantly highersarcomere solution rate(SSR)(31.40±6.48% vs 12.13±3.16%, P＜0.01),and a significantly higher level of apoptosis(34.00±0.87% vs 15.53±6.52%, P＜0.01). Furthermore, in the AF group the content of CalpainⅠwas positively related with SSR and AI (r=0.844, P＜0.01; r=0.894,P＜0.01), but the content of CalpainⅡwas not(r=0.03, P=0.89; r=0.24,P=0.39). Conelusion Compared with those with sinus rhythm, thecontent of CalpainⅡremained unchanged in the right atrium myocyteswith rheumatic chronic AF, while a marked increase of CalpainⅠandapoptosis was observed, and an obvious remodeling ofultramicrostructure. The close correlation between CalpainⅠ,ultramicrostructure changes and apoptosis indicated a possible importantrole of CalpainⅠin rheumatic chronic AF.