Change of cardiac function in experimental autoimmune myocarditis is correlated with the expression of annexin VI

The objective of this study was to investigate annexin VI expression in polypeptides-induced experimental autoimmune myocarditis (EAM) in mice, and explore the relationship between the annexin VI and cardiac function at different periods of myocarditis.

BALB/C mice were randomly divided into two main groups: control and polypeptides-induced EAM group; the PA and the PC groups represent the acute and the chronic phase of myocarditis in polypeptides-induced EAM group separately. Cardiac function was evaluated by haemodynamic measurement. Myocardial histopathological observation was performed to identify the degree of inflammation in EAM. Expression level and distribution of annexin VI were assessed by Western blotting and immunohistochemistry. We found that the polypeptides induced myocarditis and moderately severe cardiomyopathic changes. Only the PC group had significantly reduced haemodynamics. Expression levels of annexin VI decreased in the PA group and increased in the PC group.

Annexin VI is down-regulated in the acute phase of EAM, and overexpressed in the chronic phase of EAM. Annexin-VI may be responsible for the compensation and aggravation of cardiac function in different phases of EAM.