| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Research Abstract |
Dynamic process of apoptosis has not been elucidated in adult rat cardiomyocytes. Soluble Fas ligand in the prescence of actionmycine D induced apoptosis in cultured adult rat cardiomyocytes, as documented by activated caspase-3, DNA fragmentation, and apoptotic ultrastructure. In the present model, we observed 60 adult cardiomyocytes with a normal rod shape under a real-time videomicroscope continuously for 48 hours. 17 cells were unchanged and 7 cells showed oncosis (so-called necrosis) in which no beating was evident. In the remaining 36 cells of cells (apoptosis), a slow beating (17 ± 3 /min) was initiated 16 ± 1 hours later. Approximately 1 hour later, the rod cells showed long-axial shortening as bone- or club-like, or square-shaped, accompanied with faster beating rates (35 ± 7 /min). In 29 cells (type A1 and A2), marked shrinkage occurred; the cellular shape became almost completely round with a smooth surface and the beating ceased 3.0 ± 0.4 hours later. Then, smooth budding a
… More
ppeared 0.6 ± 0.2 hours later. Apoptotic bodies were found in 8 cells 10 ± 4 hours later (type A1) but not in 21 cells (type A2). In the other 7 cells (type A3), the cell surface became rough 8 ± 3 hours later and the beating ceased. Maximal beating rate was greatest in type A1 (72 ± 26 /min) and greater in type A2 (29 ± 5 /min) than in type A3 (10 ± 2 /min). Electron microscopy confirmed apoptotic ultrastructure even in the cardiomyocytes with bone, club-like, or square shapeds, suggesting that type A3 as well as Al and A2 is also under apoptotic process. A caspase inhibitor, zVAD.fmk, blocked beating, apoptotic morphology, and DNA fragmentation, indicating these dependent on caspase activation. In the caspase-dependent apoptotic process of cultued adult cardiomyocytes, beating and the following deformity of the cellular edges were the initial signs and the rate of beating was related with the subsequent three different process of apoptosis. In addition, the apoptosis was blocked by caspase inhibitor, zVAD.fmk and Ca inhibitor, nifedipine, but not by β-bl-blocker, propranolol. Less
|
