Chambers D J, Braimbridge M V, Hearse D J
Cardiovascular Research, Rayne Institute, St Thomas's Hospital, London, United Kingdom.
Can J Cardiol. 1991 Nov;7(9):410-8.
The aim of this study was to characterize the relationship of perfusate calcium concentration, contractile state and stability of the isolated crystalloid perfused working rat heart preparation, to ischemic duration and functional recovery, at a physiological perfusate calcium concentration.
In the first protocol, hearts (n = 6 per group) were aerobically perfused for up to 300 mins with Krebs Henseleit solution containing calcium concentrations (total) of 1.0, 1.2, 1.4, 1.6, 1.8 and 2.5 mmol/L (equivalent to ionized concentrations of 0.76, 0.94, 1.15, 1.21, 1.58 and 2.25 mmol/L, respectively). After 120 mins, aortic flow decreased by less than 20% in all preparations except those perfused with 1.0 mmol/L, which fell by over 60%. For subsequent studies, a calcium concentration of 1.4 mmol/L (ionized calcium 1.15 mmol/L, a value equivalent to plasma ionized calcium) was identified as ideal and shown to be associated with stable function and adequate inotropic reserve. The second protocol was as follows: In additional studies (n = 6 per group), the relationship between normothermic global ischemic duration (with or without cardioplegic arrest) and post ischemic functional recovery was characterized. Increasing the ischemic duration (10, 15, 20, 25, 30, 35 or 40 mins) progressively impaired recovery of aortic flow to 86.7 +/- 3.2%, 71.7 +/- 4.9%, 27.7 +/- 5.0%, 14.5 +/- 12.3%, 0%, 0% and 0%, respectively, in the noncardioplegia group, and to 84.7 +/- 1.7%, 85.0 +/- 2.9%, 78.0 +/- 2.4%, 56.0 +/- 7.8%, 32.2 +/- 6.0%, 6.5 +/- 3.7% and 0%, respectively, in the cardioplegia group. These results were similar to those of previous studies in which 2.5 mmol/L calcium was used in the perfusate.
Perfusion of isolated hearts with perfusate calcium concentrations up to 2.5 mmol/L (total) had no apparent detrimental effect on the stability of the preparation; however, a calcium concentration of 1.0 mmol/L resulted in a rapidly deteriorating preparation. In addition, under the conditions prevailing in the present study, a perfusate calcium content within the physiological range (1.4 mmol/L) appeared not to alter the vulnerability of the rat heart to injury during ischemia and reperfusion.
本研究旨在在生理灌注液钙浓度条件下，描述灌注液钙浓度、收缩状态与离体晶体灌注工作大鼠心脏制剂稳定性之间的关系，以及与缺血持续时间和功能恢复的关系。
在第一个方案中，心脏（每组n = 6）用含有钙浓度（总量）为1.0、1.2、1.4、1.6、1.8和2.5 mmol/L（分别相当于离子化浓度0.76、0.94、1.15、1.21、1.58和2.25 mmol/L）的克雷布斯 - 亨泽莱特溶液进行有氧灌注长达300分钟。120分钟后，除用1.0 mmol/L灌注的制剂外，所有制剂的主动脉流量下降均小于20%，而用1.0 mmol/L灌注的制剂下降超过60%。对于后续研究，确定钙浓度为1.4 mmol/L（离子化钙1.15 mmol/L，该值相当于血浆离子化钙）为理想浓度，且显示与稳定的功能和足够的变力储备相关。第二个方案如下：在额外的研究（每组n = 6）中，描述了常温全心缺血持续时间（有或无心脏停搏）与缺血后功能恢复之间的关系。在非心脏停搏组中，缺血持续时间增加（10、15、20、25、30、35或40分钟）使主动脉流量恢复逐渐受损，分别降至86.7±3.2%、71.7±4.9%、27.7±5.0%、14.5±12.3%、0%、0%和0%；在心脏停搏组中，分别降至84.7±1.7%、85.0±2.9%、78.0±2.4%、56.0±7.8%、32.2±6.0%、6.5±3.7%和0%。这些结果与之前在灌注液中使用2.5 mmol/L钙的研究结果相似。
用高达2.5 mmol/L（总量）的灌注液钙浓度灌注离体心脏对制剂稳定性无明显有害影响；然而，1.0 mmol/L的钙浓度会导致制剂迅速恶化。此外，在本研究的现有条件下，生理范围内（1.4 mmol/L）的灌注液钙含量似乎不会改变大鼠心脏在缺血和再灌注期间的损伤易感性。
