Pedersen Brian Lindegaard, Arendrup Henrik, Secher Niels H, Quistorff Bjørn
Nuclear Magnetic Resonance Centre, Department of Medical Biochemistry and Genetics, The Panum Institute, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
Exp Physiol. 2006 Jul;91(4):755-63. doi: 10.1113/expphysiol.2006.033274. Epub 2006 May 4.
This study presents a perfused preparation for evaluation of metabolism in pig intercostal muscle in vitro. Preserved vessels and nerves to an intercostal segment including two adjacent ribs allowed for tissue perfusion and electrical stimulation with measurement of contraction force, oxygen consumption and 31P-magnetic resonance spectroscopy (31P-MRS). When perfused at rest with Krebs-Ringer buffer, the preparation maintained physiological levels of phosphocreatine (PCr), inorganic phosphate (Pi), ATP and pH at a stable oxygen consumption of 0.51 +/- 0.01 micromol min(-1) g(-1) for more than 2 h. Tonic stimulation of the nerve caused anaerobic energy consumption as PCr and pH decreased, and both variables recovered after the contraction with half-time values of approximately 7 min. Force increased to 0.040 N g(-1) (range, 0.031-0.103 N g(-1)) and it gradually decreased by about 70% during the subsequent 5 min of stimulation. The calculated free ADP concentration increased from 7.4 +/- 2.1 nmol g(-1) at rest to 28 +/- 12 nmol g(-1) (mean +/- s.d.) by the end of the stimulation. Thus anaerobic ATP turnover was zero at rest, 6.1 +/- 2 micromol min(-1) g(-1) during the first minute of stimulation and 3.5 +/- 0.5 micromol min(-1) g(-1) during the two last minutes, corresponding to the drop in force. When the preparation was left unperfused, anaerobic ATP turnover averaged 0.40 +/- 0.15 micromol min(-1) g(-1) for the first 10 min. The preparation can also be applied to human intercostal muscles, as demonstrated in one preliminary experiment. The results demonstrate a stable and functional in vitro preparation of intact perfused intercostal muscles in the pig.
本研究提出了一种用于体外评估猪肋间肌代谢的灌注制备方法。保留至包含两根相邻肋骨的肋间节段的血管和神经，以便进行组织灌注和电刺激，并测量收缩力、耗氧量和31P磁共振波谱（31P-MRS）。当用 Krebs-Ringer 缓冲液在静息状态下灌注时，该制备物在0.51±0.01微摩尔·分钟-1·克-1的稳定耗氧量下，能维持磷酸肌酸（PCr）、无机磷酸盐（Pi）、三磷酸腺苷（ATP）和pH的生理水平超过2小时。对神经进行强直刺激会导致无氧能量消耗，因为PCr和pH下降，并且这两个变量在收缩后恢复，半衰期约为7分钟。力量增加到0.040 N·克-1（范围为0.031 - 0.103 N·克-1），并在随后5分钟的刺激过程中逐渐下降约70%。计算得出的游离二磷酸腺苷（ADP）浓度从静息时的7.4±2.1纳摩尔·克-1增加到刺激结束时的28±12纳摩尔·克-1（平均值±标准差）。因此，无氧ATP周转率在静息时为零，在刺激的第一分钟为6.1±2微摩尔·分钟-1·克-1，在最后两分钟为3.5±0.5微摩尔·分钟-1·克-1，与力量下降相对应。当制备物不进行灌注时，在前10分钟内无氧ATP周转率平均为0.40±0.15微摩尔·分钟-1·克-1。如在一项初步实验中所示，该制备方法也可应用于人类肋间肌。结果表明，猪完整灌注肋间肌的体外制备物稳定且功能良好。
