Laboratory of Animal Physiology, Department of Biochemistry-Biotechnology, School of Health Sciences, University of Thessaly, 41500 Larissa, Greece.
Department of Pathology, University Hospital of Larissa, 41334 Larissa, Greece.
Int J Mol Sci. 2021 Dec 21;23(1):49. doi: 10.3390/ijms23010049.
Cellular adaptive mechanisms emerging after exposure to low levels of toxic agents or stressful stimuli comprise an important biological feature that has gained considerable scientific interest. Investigations of low-dose exposures to diverse chemical compounds signify the non-linear mode of action in the exposed cell or organism at such dose levels in contrast to the classic detrimental effects induced at higher ones, a phenomenon usually referred to as hormesis. The resulting phenotype is a beneficial effect that tests our physiology within the limits of our homeostatic adaptations. Therefore, doses below the region of adverse responses are of particular interest and are specified as the hormetic gain zone. The manifestation of redox adaptations aiming to prevent from disturbances of redox homeostasis represent an area of particular interest in hormetic responses, observed after exposure not only to stressors but also to compounds of natural origin, such as phytochemicals. Findings from previous studies on several agents demonstrate the heterogeneity of the specific zone in terms of the molecular events occurring. Major factors deeply involved in these biphasic phenomena are the bioactive compound per se, the dose level, the duration of exposure, the cell, tissue or even organ exposed to and, of course, the biomarker examined. In the end, the molecular fate is a complex toxicological event, based on beneficial and detrimental effects, which, however, are poorly understood to date.
细胞适应机制在接触低水平有毒物质或应激刺激后出现，是一个重要的生物学特征，引起了相当大的科学兴趣。对不同化学化合物的低剂量暴露的研究表明，在这种剂量水平下，暴露细胞或生物体的作用模式是非线性的，与在更高剂量水平下诱导的经典有害作用形成对比，这种现象通常被称为适应原性。由此产生的表型是一种有益的影响，它在我们的生理范围内检验我们的内稳态适应能力。因此，低于不良反应区域的剂量特别有趣，并被指定为适应原性增益区。旨在防止氧化还原失衡的氧化还原适应的表现是适应原性反应中特别关注的一个领域，不仅在暴露于应激源后，而且在暴露于天然来源的化合物（如植物化学物质）后也观察到了这种适应。以前对几种药物的研究结果表明，在发生的分子事件方面，特定区域具有异质性。这些双相现象中涉及的主要因素是生物活性化合物本身、剂量水平、暴露持续时间、暴露的细胞、组织甚至器官，当然还有所检查的生物标志物。最终，分子命运是一个复杂的毒理学事件，基于有益和有害的影响，但迄今为止，这方面的了解还很差。
