National Yang-Ming University, Institute of Biophotonics, Taipei, Taiwan.
J Biomed Opt. 2011 Mar;16(3):036008. doi: 10.1117/1.3560513.
In vivo noninvasive detection of apoptosis represents a new tool that may yield a more definite diagnosis, a more accurate prognosis, and help improve therapies for human diseases. The intrinsic fluorescence of reduced nicotinamide adenine dinucleotide (NADH) may be a potential optical biomarker for the apoptosis detection because NADH is involved in the respiration for the mitochondrial membrane potential (ΔΨ) formation and adenosine-5'-triphosphate (ATP) synthesis, and the depletion of ΔΨ and ATP level is the hallmark of apoptosis. We have previously observed the NADH fluorescence lifetime change is associated with staurosporine (STS)-induced mitochondria-mediated apoptosis. However, its relationship with mitochondrial functions such as ΔΨ, ATP, and oxygen consumption rate is not clear. In this study, we investigated this relationship. Our results indicate that the NADH fluorescence lifetime increased when ΔΨ and ATP levels were equal to or higher than their values of controls and decreased before the depletion of ΔΨ and ATP, and the oxygen consumption rate did not change. These findings suggest that the increased NADH fluorescence lifetime in STS-induced cell death occurred before the depletion of ΔΨ and ATP and activation of caspase 3, and was not simply caused by cellular metabolic change. Furthermore, the NADH fluorescence lifetime change is associated with the pace of apoptosis.
在体无创检测细胞凋亡为临床提供了一种新的诊断方法，它可以提供更准确的预后判断，并有助于改善人类疾病的治疗方法。还原型烟酰胺腺嘌呤二核苷酸（NADH）的固有荧光可能是细胞凋亡检测的潜在光学生物标志物，因为 NADH 参与线粒体膜电位（ΔΨ）形成和三磷酸腺苷（ATP）合成的呼吸作用，而 ΔΨ 和 ATP 水平的耗竭是细胞凋亡的标志。我们之前观察到，NADH 荧光寿命的变化与星形孢菌素（STS）诱导的线粒体介导的细胞凋亡有关。然而，其与线粒体功能（如 ΔΨ、ATP 和耗氧量）的关系尚不清楚。在这项研究中，我们对此进行了研究。结果表明，当 ΔΨ 和 ATP 水平与对照组相比相等或更高时，NADH 荧光寿命增加，而在 ΔΨ 和 ATP 耗竭之前则降低，耗氧量没有变化。这些发现表明，STS 诱导的细胞死亡中 NADH 荧光寿命的增加发生在 ΔΨ 和 ATP 耗竭以及半胱天冬酶 3 激活之前，并非仅仅是由细胞代谢变化引起的。此外，NADH 荧光寿命的变化与细胞凋亡的速度有关。
