Cytosolic-Ca2+ and coxsackievirus B-3-induced apoptosis in cultured cardiomyocytes of rats

ATM: To explore the role of cytosolic free calcium ([Ca2+](i)) in apoptosis induced by coxsackievirus Bg (CVB3) in cultured cardiomyocytes of rats. ME THODS: Primary cultured cardiomyocyte was prepared from Wistar rats ages 2 - 3 d. The apoptosis in cardiomyocyte was determined by terminated deoxynuc leotide transferase directed d-UTP nick and end labeling (TUNEL) method, an d the apoptosis was observed under a transmission electron microscope. [Ca2 +](i) in single,cardiomyocyte loaded with Flue 3 AM was measured by confoca l microsorope. RESULTS: (1) The concentration of CVB3 in the medium reached the peak at 24 h after CVB3 infection. (2) The apoptotic cells were not fo und in CVB3-infected cardiomyocyte in first 10 h, but amounted to 5% at 17 h, 60% at 24 h, and 90% at 36 h. (3) The peak value of [Ca2+](i) elevation reached at 17 h after CVB3 infection (P < 0.01). (4) The characteristics of apoptosis was also seen by transmission electron microscope. CONCLUSION: C VB3 induced the apoptosis in cultured cardiomyocyte, and [Ca2+](i) mobiliza tion was involved in the signal transduction process in apoptosis cells, an d played an important role especially in the early stage of apoptosis induc ed by CVB3.