Cytosolic-Ca2+ and coxsackievirus B3-induced apoptosis in cultured cardiomyocytes of rats.

Aim: To explore the role of cytosolic free calcium ([Ca2+]i) in apoptosis induced by coxsackievirus B3 (CVB3) in cultured cardiomyocytes of rats.

Methods: Primary cultured cardiomyocyte was prepared from Wistar rats ages 2-3 d. The apoptosis in cardiomyocyte was determined by terminated deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) method, and the apoptosis was observed under a transmission electron microscope. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal 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 found 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: CVB3 induced the apoptosis in cultured cardiomyocyte, and [Ca2+]i mobilization was involved in the signal transduction process in apoptosis cells, and played an important role especially in the early stage of apoptosis induced by CVB3.