基于NADH荧光的组织病理生理状态多参数在体监测与评价

In vivo multiparametric monitoring of tissue pathophysiological conditions based on NADH fluorescence

组织病理生理状态的实时多参数评价,无论在动物实验研究还是临床应用中均具有重要价值,一直是生命科学与医学研究者们广泛关注的热点.众所周知,临床手术过程或重症监护病房中,患者病理生理状态的实时监测是十分必需的.心、脑等重要组织脏器是否处于缺血缺氧等危急状态直接关系到病人的存活与否;早期发现术中和术后次要脏器的微循环障碍有助于提高器官移植等手术的成功率和降低术后并发症的发生率.临床常规使用的监测指标,如血压、心电、脉搏等,在生命指征的实时评价中发挥了重要作用.然而,目前的常规指标尚不足以从分子水平反映局部组织病理生理状态的早期改变.NADH是细胞线粒体中氧化还原呼吸链上的内源性关键分子,具有自发荧光性质,可作为一项灵敏的内源性含氧状态指标来反映机体的代谢状态和细胞活力.本文介绍了基于NADH自发荧光信号的细胞氧化还原状态在体监测方法,从分子水平预警机体的活力情况,结合微循环血流、血氧饱和度等多种生理参数的同步并行监测,不仅可在活体动物体内进行疾病的病理生理学机制研究和新药的药效评价,还有望应用于临床外科手术和重症监护病房,为机体活力和生命指征的实时监护提供分子水平的动态信息.目前,NADH荧光一维信号的获取技术发展最为成熟,可实现从离体、活细胞、活体动物乃至临床水平的实时动态监测,已处于临床推广应用阶段.二维动态成像也已经发展到活体动物实验阶段.三维成像由于受制于NADH荧光的穿透能力,只能在冷冻组织切片上实现.如何突破因高散射所致的荧光穿透能力受限的瓶颈,最大限度地减少环境因素对荧光信号的干扰,在分子水平实现组织病理生理状态的实时多参数评价,是生物医学光子学领域面临的巨大挑战.

Real-time multiparametric evaluation of tissue pathophysiological conditions is of great value in animal experiments and for clinic applications,and is receiving more and more attention by researchers in life sciences and medicine.It is well known that the real-time monitoring of pathophysiological conditions in patients is required during surgical procedures and in intensive care units（ICUs）.Whether a critical condition such as ischemia and hypoxia can be detected in vital organs,such as heart and brain,is directly related to patient survival.Early detection of microcirculatory disturbances in non-vital organs will also help to increase the success rate of surgeries such as organ transplantation,and decrease the incidence of post-operative complications.Conventional parameters,such as blood pressure,electrocardiogram and pulse,which are monitored in clinics,play important roles in the real-time evaluation of vital signs;however,they do not provide enough information to expose early changes in local tissue pathophysiological conditions at the molecular level.NADH is an intrinsic autofluorescent molecule involved in the redox reactions of the mitochondrial respiratory chain and serves as a sensitive marker,reflecting metabolic states and cell vitality.This paper introduces in vivo techniques to monitor the cellular metabolic states based on NADH autofluorescence.This method,combined with synchronous parallel monitoring of multiple parameters such as microcirculatory blood flow and hemoglobin oxygenation,will not only be useful in studies of pathophysiological mechanisms and evaluation of drug effects in vivo,but could also be clinically applied in surgeries and ICUs to provide real-time dynamic information of vital signs.At present,the technique of monitoring one-dimensional NADH fluorescent signals is well developed,and has been applied from in vitro experiments to living cells,animals,and in clinical studies.The two-dimensional imaging technique has been previously used in vivo.However,three-dimensional imaging has only been successful in frozen tissue slices due to the limited penetration of NADH.There are some large challenges that need to be addressed in the future,such as how to overcome the bottleneck of limited light penetration caused by high scattering in biological tissues;and how to maximally reduce environmental interference of fluorescent signals.Once these problems have been overcome,it should be possible to achieve real-time multiparametric monitoring of tissue pathophysiological conditions at a molecular level.