Camara A K S, Chen Q, An J, Novalija E, Riess M L, Rhodes S S, Stowe D F
Anesthesiology Research Laboratories, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226, USA.
J Cardiovasc Surg (Torino). 2004 Feb;45(1):1-13.
[MgCl(2)] and [CaCl(2)] may modify the cardioprotective effects of hyperkalemic cardioplegia (CP). We changed [MgCl(2)] and [CaCl(2)] in a CP solution to examine their effects on [Ca(2+)]i transients and cardiac function before and after global normothermic ischemia.
After stabilization and loading of indo 1-AM in Kreb's solution (KR), each heart was perfused with either KR or 1 of 4 CP solutions before 37 degrees C, 30 min ischemia followed by reperfusion with KR. The KR solution contained, in mM, 4.5 KCl, 2.4 MgCl(2) and 2.5 CaCl(2); the CP solutions had in addition to 18 KCl: CP 1 (control CP): 2.4 MgCl(2), 2.5 CaCl(2); CP 2: 7.2 MgCl(2), 2.5 CaCl(2); CP 3, 7.2 MgCl(2), 1.25 CaCl(2); CP 4: 2.4 MgCl(2), 1.25 CaCl(2).
In the KR group [Ca(2+)]i markedly increased on early reperfusion while functional return (LVP, dLVP/dt((max and min))) was much reduced; each CP group led to reduced [Ca(2+)]i loading and improved function. The rates of cytosolic Ca(2+) fluxes (d[Ca(2+)]/dt(max) and d[Ca(2+)]/dt(min)) increased significantly compared to baseline in the KR group, but were mostly suppressed in the CP groups, and d[Ca(2+)]/dt(min) was lower after CP 4 compared to CP 1 on reperfusion. At 60 min reperfusion, LVP area to [Ca(2+)] area and cardiac efficiency to phasic [Ca(2+)] relationships were shifted after KR, but not after CP 1-4. With similar functional recovery, [Ca(2+)] transient and [Ca(2+)] area were significantly lower after CP 4 than after CP 1.
Increasing [MgCl(2)] (CP 2 and 3) did not improve cardiac function or reduce Ca(2+) transients on reperfusion better than the other CP groups, but reducing [CaCl(2)] (CP 3 and 4) was more effective in reducing [Ca(2+)] transients on reperfusion after global ischemia.
氯化镁（MgCl₂）和氯化钙（CaCl₂）可能会改变高钾停搏液（CP）的心脏保护作用。我们改变CP溶液中的MgCl₂和CaCl₂浓度，以研究其对常温全心缺血前后细胞内钙离子（Ca²⁺）瞬变及心脏功能的影响。
在克雷布斯溶液（KR）中稳定加载indo 1-AM后，每颗心脏在37℃下分别用KR或4种CP溶液之一灌注，30分钟缺血后再用KR灌注。KR溶液含（以毫摩尔计）4.5氯化钾（KCl）、2.4氯化镁（MgCl₂）和2.5氯化钙（CaCl₂）；CP溶液除含18 KCl外：CP 1（对照CP）：2.4 MgCl₂，2.5 CaCl₂；CP 2：7.2 MgCl₂，2.5 CaCl₂；CP 3：7.2 MgCl₂，1.25 CaCl₂；CP 4：2.4 MgCl₂，1.25 CaCl₂。
KR组再灌注早期细胞内Ca²⁺显著增加，而功能恢复（左室压（LVP）、最大和最小左室压变化率（dLVP/dt（max和min）））明显降低；各CP组均使细胞内Ca²⁺负荷降低，功能改善。与KR组基线相比，KR组胞浆Ca²⁺通量速率（d[Ca²⁺]/dt（max）和d[Ca²⁺]/dt（min））显著增加，但在CP组大多受到抑制，再灌注时CP 4组的d[Ca²⁺]/dt（min）低于CP 1组。再灌注60分钟时，KR组后LVP面积与Ca²⁺面积及心脏效率与阶段性Ca²⁺的关系发生改变，但CP 1 - 4组后未改变。在功能恢复相似的情况下，CP 4组后的Ca²⁺瞬变和Ca²⁺面积显著低于CP 1组。
增加MgCl₂（CP 2和3）在再灌注时改善心脏功能或减少Ca²⁺瞬变方面并不比其他CP组更好，但降低CaCl₂（CP 3和4）在全心缺血后再灌注时减少Ca²⁺瞬变方面更有效。
