Expression of SSB Following Early Myocardial Ischemia in Rats

Objective To investigate the expression of Sj?gren’s syndrome antigen B (SSB) gene and SSB protein in the early ischemic myocardium in rats. Methods Adult healthy Sprague-Dawley rats were randomly divided into groups of operation 〔myocardial ischemia (MI) and non-ischemia (NI)〕, non-operation (NO) and sham-operation (SO) (n=6 for MI and NI; n=4 for NO and SO). According to time of ischemia, it was then divided into groups of 0 min, 15 min, 30 min, 60 min, 120 min, and 240 min. The expression of SSB gene in the myocardium was examined by real-time PCR, and the expression of SSB protein was examined by Western blot and immunofluorescence staining. Results The expressions of SSB gene was down-regulated at early stage of ischemia. There was significant difference between 0 min and 120 min at the level of expression of SSB gene in MI group, so did that between 120 min group and NO group (P<0.05). The expression of SSB protein at 60 min after ischemia was significantly decreased compared with that in the group of 0 min (P<0.05). The expression of SSB protein in NI groups was significantly higher than that in MI groups at the time of 60 min and 120 min after myocardial ischemia (P<0.05). Additionally, the expression of SSB protein was mainly located in the myocardial nucleus, myocardial plasma, and plasma membrane of partial myocardiocytes according to the result of immunofluorescence staining. Conclusion SSB may participate in pathophysiologic regulation process in myocardial cells at the early stage of myocardial ischemia in rats.