Many neurodegenerative diseases are known to occur and progress because of oxidative stress, the presence of reactive oxygen species (ROS) in excess of the cellular defensive capabilities.
Generally, ROS are tightly regulated in balance with cellular defensive antioxidants, such as catalase and SOD, and can participate in a multitude of cellular functions including signal transduction [31].
Although our old dogs were clinically healthy, our observations indicate that the aged colon appears to have an increased risk of inflammation and a decreased functionality of cellular defensive mechanisms.
For example, herpes viruses encode in excess of 200 open reading frames, the majority of which have roles in antagonizing cellular defensive processes (for review, see Amsler et al., 2013).
Nrf2 is a key redox-sensitive transcription factor that regulates the expression of endogenous antioxidants, phase II detoxification enzymes, and other cellular defensive proteins in response to cellular stress.
Mechanisms of cellular defensive response to ischaemic stress and pharmacological interventions were investigated using animal, tissue, and subcellular models, particularly in mice, rats, and rabbits, and, to the lesser extent, large animals.
