Orita H, Fukasawa M, Hirooka S, Uchino H, Fukui K, Kohi M, Washio M
Second Department of Surgery, Yamagata University School of Medicine, Japan.
Cardiovasc Drugs Ther. 1993 Aug;7(4):713-20. doi: 10.1007/BF00877825.
The purpose of the present study was to evaluate the functional and biochemical effects of diltiazem (DTZ) on cardiac myocytes incubated under hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days with MCDB 107 medium. Then, myocytes (12.5 x 10(5) myocytes/flask) were incubated at 4 degrees C for 24 hours in media with or without DTZ at concentrations of 0 M (group C), 10(-7) M (Group D1), 10(-6) M (group D2), 10(-5) M (group D3), or 10(-4) M (group D4). After 24 hours at 4 degrees C, CPK and LDH were measured. The myocytes were then cultured for 24 hours at 37 degrees C to evaluate the recovery of the myocyte beating rate. In group C (n = 7), the recovery ratio of the myocyte beating rate was 29.9% of control (beating rate prior to hypothermic incubation). Groups D1 and D2 (n = 7 each) had approximately the same recovery ratios as group C (24.0% and 24.7%, respectively); however, groups D3 and D4 (n = 7 each) showed no beating rate recovery. Release of CPK and LDH in group C was 112.3 mIU/flask and 457.4 mIU/flask, respectively. Groups D1 and D2 showed no significant differences in both enzymes compared to group C. However, the levels of CPK were significantly higher in group D4 (203.3, p < 0.05), and LDH levels were significantly higher in groups D3 and D4 (669.3, p < 0.05; 883.4, p < 0.02). In conclusion, DTZ showed no protective effects on hypothermic injury to immature cardiac myocytes; moreover, it accelerated cellular injury at the concentrations of 10(-5) and 10(-4) M both functionally and biochemically. Therefore, diltiazem may not be suitable for cardiac preservation during the neonatal period.
本研究的目的是评估地尔硫䓬（DTZ）对在低温条件下培养的心肌细胞的功能和生化影响。从新生大鼠心室分离心肌细胞，并用MCDB 107培养基培养4天。然后，将心肌细胞（12.5×10⁵个细胞/培养瓶）在4℃下于含有或不含有浓度为0 M（C组）、10⁻⁷ M（D1组）、10⁻⁶ M（D2组）、10⁻⁵ M（D3组）或10⁻⁴ M（D4组）的DTZ的培养基中孵育24小时。在4℃下孵育24小时后，测量肌酸磷酸激酶（CPK）和乳酸脱氢酶（LDH）。然后将心肌细胞在37℃下培养24小时，以评估心肌细胞搏动率的恢复情况。在C组（n = 7）中，心肌细胞搏动率的恢复率为对照（低温孵育前的搏动率）的29.9%。D1组和D2组（每组n = 7）的恢复率与C组大致相同（分别为24.0%和24.7%）；然而，D3组和D4组（每组n = 7）未显示搏动率恢复。C组中CPK和LDH的释放分别为112.3 mIU/培养瓶和457.4 mIU/培养瓶。与C组相比，D1组和D2组在这两种酶方面均无显著差异。然而，D4组中CPK水平显著更高（203.3，p < 0.05），D3组和D4组中LDH水平显著更高（669.3，p < 0.05；883.4，p < 0.02）。总之，DTZ对未成熟心肌细胞的低温损伤无保护作用；此外，在10⁻⁵和10⁻⁴ M浓度下，它在功能和生化方面加速了细胞损伤。因此，地尔硫䓬可能不适用于新生儿期的心脏保存。
