Masuda Kazumi, Truscott Kent, Lin Ping-Chang, Kreutzer Ulrike, Chung Youngran, Sriram Renuka, Jue Thomas
Faculty of Human Sciences, Institute of Human and Social Science, Kanazawa University, Kanazawa, Japan.
Eur J Appl Physiol. 2008 Sep;104(1):41-8. doi: 10.1007/s00421-008-0775-x. Epub 2008 May 31.
The standard method for determining the myoglobin (Mb) concentration in blood-perfused tissue often relies on a simple but clever differencing algorithm of the optical spectra, as proposed by Reynafarje. However, the underlying assumptions of the differencing algorithm do not always lead to an accurate assessment of Mb concentration in blood-perfused tissue. Consequently, the erroneous data becloud the understanding of Mb function and oxygen transport in the cell. The present study has examined the Mb concentration in buffer and blood-perfused mouse heart. In buffer-perfused heart containing no hemoglobin (Hb), the optical differencing method yields a tissue Mb concentration of 0.26 mM. In blood-perfused tissue, the method leads to an overestimation of Mb. However, using the distinct (1)H NMR signals of MbCO and HbCO yields a Mb concentration of 0.26 mM in both buffer- and blood-perfused myocardium. Given the NMR and optical data, a computer simulation analysis has identified some error sources in the optical differencing algorithm and has suggested a simple modification that can improve the Mb determination. Even though the present study has determined a higher Mb concentration than previously reported, it does not alter significantly the equipoise PO(2), the PO(2) where Mb and O(2) contribute equally to the O(2) flux. It also suggests that any Mb increase with exercise training does not necessarily enhance the intracellular O(2) delivery.
测定血液灌注组织中肌红蛋白（Mb）浓度的标准方法通常依赖于Reynafarje提出的一种简单而巧妙的光谱差分算法。然而，差分算法的基本假设并不总能准确评估血液灌注组织中的Mb浓度。因此，错误的数据模糊了对细胞中Mb功能和氧运输的理解。本研究检测了缓冲液灌注和血液灌注的小鼠心脏中的Mb浓度。在不含血红蛋白（Hb）的缓冲液灌注心脏中，光学差分法得出的组织Mb浓度为0.26 mM。在血液灌注组织中，该方法会导致对Mb的高估。然而，利用MbCO和HbCO独特的氢核磁共振（¹H NMR）信号，在缓冲液灌注和血液灌注的心肌中得出的Mb浓度均为0.26 mM。根据核磁共振和光学数据，计算机模拟分析确定了光学差分算法中的一些误差来源，并提出了一种可改进Mb测定的简单修正方法。尽管本研究测定的Mb浓度高于先前报道的浓度，但它并未显著改变平衡氧分压（PO₂），即Mb和O₂对氧通量贡献相等时的PO₂。这也表明，运动训练导致的任何Mb增加不一定会增强细胞内的氧输送。
