Objective: To study the dynamic changes of Bax and Bcl-2 genes protein expression in cardiomyocytes and the relationship between the changes and cardiomyocyte apoptosis in spontaneously hypertensive rats (SHR). Methods: Bax and Bcl-2 genes protein expression and cardiomyocyte apoptosis were tested by immunohistochemical method and in situ TdT-mediated dUTP nick end labeling(TUNEL). Results: (1)The cardiomyocyte apoptosis and Bax gene protein expression were notably increased in 1-month-old SHR group (NLVH group) and 18~20-month-old SHR group (CHF group) and Bax gene protein expression was positively bound up with cardiomyocyte apoptosis(all P values less than 0.01). (2)The cardiomyocyte apoptosis was significantly decreased but Bcl-2 gene protein expression remarkably increased in 10-month-old SHR group (LVH group) and Bcl-2 gene protein expression was negatively related to cardiomyocyte apoptosis (all P values less than 0.01). (3)The ratio of Bcl-2 to Bax (an inverse index of cell susceptibility of apoptosis) was markedly lowered in NLVH group and CHF group but that was outstandingly raised in LVH group and the ratio of Bcl-2 to Bax was inversely correlated with cardiomyocyte apoptosis(all P values less than 0.01). Conclusion: The dynamic changes of Bax and Bcl-2 genes as well as cardiomyocyte apoptosis exist in SHR
moreover
upregulation of Bax gene protein expression may be associated with the increase of cardiomyocyte apoptosis and CHF of SHR
whereas upregulation of Bcl-2 gene protein expression may be bound up with the decrease of cardiomyocyte apoptosis and LVH of SHR. Therefore
the dynamic changes of Bax and Bcl-2 genes protein expression may play an important role in cardiomyocyte apoptosis and heart remodeling of SHR.