Xia Z F, Zhao P, Horton J W
Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9160, USA.
Am J Physiol Heart Circ Physiol. 2001 Apr;280(4):H1916-22. doi: 10.1152/ajpheart.2001.280.4.H1916.
Cutaneous burn trauma causes cardiac contraction and relaxation defects, but the mechanism is unclear. Previous studies suggest that burn-related changes in myocyte handling of calcium may play an important role in postburn cardiac dysfunction. With the use of a high dissociation constant (K(d)) calcium indicator 1,2-bis(2-amino-5,6-difluorophenoxy)-ethane-N,N,N',N'-tetraacetic acid (TF-BAPTA) and (19)F NMR spectroscopy, this study examined the correlation between the changes in cytosolic free calcium concentration (Ca(2+)) and cardiac function after burn trauma. Sprague-Dawley rats were given scald burn (over 40% of the total body surface area) or sham burn. Twenty-four hours later, the hearts were excised and perfused by the Langendorff method with a modified phosphate-free Krebs-Henseleit bicarbonate buffer. Left ventricular (LV) developed pressure (LVDP), calculated from peak systolic LV pressure and LV end-diastolic pressure, was assessed through a catheter attached to an intraventricular balloon. At the same time, (31)P and (19)F NMR spectroscopy was performed before and after TF-BAPTA loading. LVDP measured in hearts from burned rats was <40% than that measured in hearts from sham burn rats (65 +/- 6 vs. 110 +/- 12 mmHg, P < 0.01); Ca(2+) was increased fourfold in hearts from the burned group compared with that measured in the sham burn group (0.807 +/- 0.192 vs. 3.891 +/- 0.929 microM). Loading TF-BAPTA in hearts transiently decreased LVDP by 15%. Phosphocreatine-to-P(i) ratio decreased, but ATP and intracellular pH remained unchanged by either TF-BAPTA loading or burn trauma. In conclusion, burn trauma impaired cardiac contractility, and this functional defect was paralleled by a significant rise in Ca(2+) in the heart.
皮肤烧伤创伤会导致心脏收缩和舒张功能缺陷，但其机制尚不清楚。先前的研究表明，烧伤相关的心肌细胞钙处理变化可能在烧伤后心脏功能障碍中起重要作用。本研究使用高解离常数（K(d)）钙指示剂1,2-双（2-氨基-5,6-二氟苯氧基）乙烷-N,N,N',N'-四乙酸（TF-BAPTA）和（19）F核磁共振波谱，研究了烧伤创伤后细胞溶质游离钙浓度（Ca(2+)）变化与心脏功能之间的相关性。将Sprague-Dawley大鼠进行烫伤（超过全身表面积的40%）或假烧伤。24小时后，取出心脏，用改良的无磷酸盐Krebs-Henseleit碳酸氢盐缓冲液通过Langendorff方法进行灌注。通过连接到心室内球囊的导管评估由左心室（LV）收缩压峰值和LV舒张末期压力计算得出的左心室（LV）发育压力（LVDP）。同时，在加载TF-BAPTA之前和之后进行（31）P和（19）F核磁共振波谱分析。烧伤大鼠心脏中测量的LVDP比假烧伤大鼠心脏中测量的LVDP低<40%（65±6 vs. 110±12 mmHg，P<0.01）；与假烧伤组相比，烧伤组心脏中的Ca(2+)增加了四倍（0.807±0.192 vs. 3.891±0.929 microM）。在心脏中加载TF-BAPTA会使LVDP暂时降低15%。磷酸肌酸与无机磷（P(i)）的比值降低，但加载TF-BAPTA或烧伤创伤均未使ATP和细胞内pH发生变化。总之，烧伤创伤损害了心脏收缩力，并且这种功能缺陷与心脏中Ca(2+)的显著升高平行。
