科研之友
微信
新浪微博
Facebook
分享链接
摘要
A linear relationship between skeletal muscle venous (CTven) and oxygenated (AHbMbO2,N) or deoxygenated (AHHbMbN) near -infrared spectroscopy (NIRS) signals suggest a main hemoglobin (Hb) contribution to the NIRS signal. However, experimental, and computational evidence supports a significant contribution of myoglobin (Mb) to the NIRS. Venous and NIRS measure-ments from a canine model of muscle oxidative metabolism (Sun Y, Ferguson BS, Rogatzki MJ, McDonald JR, Gladden LB. Med Sci Sports Exerc 48(10):2013-2020, 2016) were integrated into a computational model of muscle O2 transport and utiliza-tion to evaluate whether the relationship between venous and NIRS oxygenation can be affected by a significant Mb contribu-tion to the NIRS signals. The mathematical model predicted well the measure of the changes of CTven and NIRS signals for different O2 delivery conditions (blood flow, arterial O2 content) in muscle at rest (T1, T2) and during contraction (T3). Furthermore, computational analysis indicates that for adequate O2 delivery, Mb contribution to NIRS signals was significant (20%-30%) even in the presence of a linear CTven-NIRS relationship; for a reduced O2 delivery the nonlinearity of the CTven-NIRS relationship was related to the Mb contribution (50%). In this case (T3), the deviation from linearity is observed when O2 deliv-ery is reduced from 1.3 to 0.7 L kg 1 center dot min 1 (CTven < 10 mLO2 100 mL 1) and Mb saturation decreased from 85% to 40% corre-sponding to an increase of the Mb contribution to AHHbMbN from 15% to 50% and the contribution to AHbMbO2,N from 0% to 30%. In contrast to a common assumption, our model indicates that both NIRS signals (AHHbMbN and AHbMbO2,N are signifi- cantly affected by Hb and Mb oxygenation changes.NEW & NOTEWORTHY Within the near-infrared spectroscopy (NIRS) signal, the contribution from hemoglobin is indistinguish-able from that of myoglobin. A computation analysis indicates that a linear relationship between muscle venous oxygen content and NIRS signals does not necessarily indicate a negligible myoglobin contribution to the NIRS signal. A reduced oxygen deliv-ery increases the myoglobin contribution to the NIRS signal. The integrative approach proposed is a powerful way to assist in interpreting the elements from which the NIRS signals are derived.
