Wang, Tian, Reddy, Nalawade, Barrett, Gonzalez-Lima, Liu (2017) Up-regulation of cerebral cytochrome-c-oxidase and hemodynamics by transcranial infrared laser stimulation: A broadband near-infrared spectroscopy study Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 37(12) 3789-3802


Transcranial infrared laser stimulation (TILS) is a noninvasive form of brain photobiomulation. Cytochrome-c-oxidase (CCO), the terminal enzyme in the mitochondrial electron transport chain, is hypothesized to be the primary intracellular photoacceptor. We hypothesized that TILS up-regulates cerebral CCO and causes hemodynamic changes. We delivered 1064-nm laser stimulation to the forehead of healthy participants ( n = 11), while broadband near-infrared spectroscopy was utilized to acquire light reflectance from the TILS-treated cortical region before, during, and after TILS. Placebo experiments were also performed for accurate comparison. Time course of spectroscopic readings were analyzed and fitted to the modified Beer-Lambert law. With respect to the placebo readings, we observed (1) significant increases in cerebral concentrations of oxidized CCO (Δ[CCO]; >0.08 µM; p < 0.01), oxygenated hemoglobin (Δ[HbO]; >0.8 µM; p < 0.01), and total hemoglobin (Δ[HbT]; >0.5 µM; p < 0.01) during and after TILS, and (2) linear interplays between Δ[CCO] versus Δ[HbO] and between Δ[CCO] versus Δ[HbT]. Ratios of Δ[CCO]/Δ[HbO] and Δ[CCO]/Δ[HbT] were introduced as TILS-induced metabolic-hemodynamic coupling indices to quantify the coupling strength between TILS-enhanced cerebral metabolism and blood oxygen supply. This study provides the first demonstration that TILS causes up-regulation of oxidized CCO in the human brain, and contributes important insight into the physiological mechanisms.

经颅红外激光刺激(TILS)是大脑光生物模拟的一种非侵入性形式。假设线粒体电子传输链中的末端酶细胞色素c-氧化酶(CCO)是主要的细胞内光受体。我们假设TILS上调大脑CCO并引起血液动力学变化。我们向健康参与者(n = 11)的前额提供了1064 nm激光刺激,而宽带近红外光谱仪被用来在TILS之前,之中和之后从TILS处理的皮质区域获取光反射率。还进行了安慰剂实验以进行准确比较。分析了光谱读数的时程,并使其符合经修改的比尔-朗伯定律。关于安慰剂的读数,我们观察到(1)氧化CCO(Δ[CCO];> 0.08 µM; p <0.01),氧化血红蛋白(Δ[HbO];> 0.8 µM; p <0.01)的脑浓度显着增加。 )和TILS期间和之后的总血红蛋白(Δ[HbT];> 0.5 µM; p <0.01),以及(2)Δ[CCO]与Δ[HbO]之间以及Δ[CCO]与Δ[HbT之间]。引入Δ[CCO] /Δ[HbO]和Δ[CCO] /Δ[HbT]之比作为TILS诱导的代谢-血液动力学耦合指数,以量化TILS增强的脑代谢与血氧供应之间的耦合强度。这项研究首次证明了TILS会导致人脑中氧化CCO的上调,并为生理机制做出重要贡献。


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