Kanazawa University, Kanazawa 920-1192, Japan.
Adv Exp Med Biol. 2010;662:323-8. doi: 10.1007/978-1-4419-1241-1_46.
In order to obtain evidence that Mb releases O(2) during muscle contraction, we have set up a buffer-perfused hindlimb rat model and applied NIRS to detect the dynamics of tissue deoxygenation during contraction. The NIRS signal was monitored on hindlimb muscle during twitch contractions at 1 Hz, evoked via electrostimulator at different submaximal levels. The hindlimb perfusion was carried out by perfusion of Krebs Bicarbonate buffer. The NIRS still detected a strong signal even under Hb-free contractions. The deoxygenation signal (Delta[deoxy]) was progressively increased at onset of the contraction and reached the plateau under both blood- and buffer-perfused conditions. However, the amplitude of Delta[deoxy] during steady state continued to significantly increase as tension increased. The tension-matched comparison of the Delta[deoxy] level under buffer-perfused and blood perfused conditions indicate that Mb can contribute approximately 50% to the NIRS signal. These results clarify the Mb contribution to the NIRS signal and show a falling intracellular PO(2) as workload increases.
为了获得 Mb 在肌肉收缩过程中释放 O(2)的证据，我们建立了缓冲液灌注的大鼠后肢模型，并应用近红外光谱技术（NIRS）来检测收缩过程中组织去氧动力学。通过在不同次最大水平下用电刺激器诱发 1 Hz 的抽搐收缩，监测后肢肌肉的 NIRS 信号。通过灌注 Krebs 碳酸氢盐缓冲液进行后肢灌注。即使在没有 Hb 的收缩情况下，NIRS 仍然检测到很强的信号。在收缩开始时，去氧信号（Delta[deoxy]）逐渐增加，并在血液和缓冲液灌注条件下达到平台期。然而，在稳定状态下，Delta[deoxy]的幅度随着张力的增加而继续显著增加。缓冲液灌注和血液灌注条件下张力匹配的 Delta[deoxy]水平比较表明，Mb 可以对 NIRS 信号做出约 50%的贡献。这些结果阐明了 Mb 对 NIRS 信号的贡献，并表明随着工作负荷的增加，细胞内 PO(2)下降。
