激光或单色光的强度可以分为低、中和高三个等级，其生物调节作用称为光生物调节作用。从内稳态的角度综述相应的研究进展。功能内稳态是维持功能充分稳定发挥的负反馈机制，它可以抵抗低于阈值的内外干扰，但被高于阈值的应激所打破。处于内稳态的应激称为成功应激，远离内稳态的应激称为慢性应激。成功应激打破一个功能内稳态之后，能够建立另一个功能内稳态。弱光可以调节慢性应激，但对成功应激或处于功能内稳态的功能无效。细胞的多种膜蛋白可以协同介导低强度单色光的自适应调节。内源性光敏剂介导中强度单色光的调节作用。弱光可以用于诊断功能内稳态或成功应激本身和其形成过程。并讨论了光生物调节作用在外科快速康复中的应用。

Photobiomodulation (PBM) is a biomodulation of laser irradiation (LI) or monochromatic light. The LI may be low intensity LI (LIL) at about 10 mW/cm2, moderate intensity LI (MIL) at 0.1~1.0 W/cm2 or high intensity LI. The progress in PBM studies is reviewed from homeostatic viewpoint in this paper. Function-specific homeostasis (FSH) is a negative-feedback response of a biosystem to maintain the function-specific conditions inside the biosystem so that the function is perfectly performed. FSH can resist internal or/and external disturbance under threshold, but can be disrupted by FSH-specific stress (FSS). There is a FSS-specific homeostasis (FSSH) in which a FSS not only disrupts the original FSH, but also establishes a new FSH so that it is called a successful stress. Low level LI (LLL) has been so defined that it cannot modulate a successful stress or a function in its FSH, but it can modulate a FSS far from its FSSH. LIL might be coordinately mediated by many kinds of proteins in membrane of cells or cellular organellae so that the FSH can be self-adaptively established. MIL might be mediated by endogenetic photosensitive proteins. LLL can be used to diagnose the process for a function to establish its FSH or for a FSS to establish its FSSH and the FSH or FSSH itself. The applications of PBM in enhanced recovery after surgery are also discussed.