Introduction: Multiple sclerosis (MS) is a chronic, multifactorial disease of the central nervous system (CNS) characterized by inflammation and demyelination, which results in a heterogeneous array of symptoms including deleterious effects on motor, visual, sensory, and autonomic nervous system function. Research has demonstrated a link between MS and oxidative stress. Oxidative stress is a crucial factor in MS pathogenesis by ameliorating leukocyte migration, contributing to oligodendrocyte damage and axonal injury. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are created in CNS of MS patients mainly by activated macrophages and microglia structures responsible for demyelination and axons disruption. Therefore, increasing antioxidant levels to counter oxidative stress has been proposed as a potential treatment for MS.
Methods: A review literature search of eligible studies was conducted in PubMed database from 2015 to 2021 for studies evaluating the association between Antioxidant treatment, oxidative stress and multiple sclerosis using the following search strategy: ("oxidative stress" OR "RONS") AND ("multiple sclerosis" or "MS") AND (“antioxidant defence” or “antioxidant supplementation” as keywords. We included studies who analyzed malondialdehyde (MDA), total antioxidant capacity (TAC) and antioxidant enzymes [superoxide dismutase (SOD), and glutathione peroxidase (GPx)] activity and oxidative stress biomarkers.
Results: The results of our review article suggest that while reduction in oxidative stress markers (e.g. malondialdehyde (MDA), tumor necro- sis factor (TNF)-α, interleukin (IL)-4, IL-6, IL-1β, nitric oxide, and total oxidative stress levels) from antioxidant supplementation has been observed, these studies have demonstrated very limited effects on MS symptoms. One original study suggests that CoQ10 supplements at a dose of 500 mg/day can decrease oxidative stress and increase antioxidant enzyme activity in patients with relapsing-remitting MS. Another study reported decreasing the population and activation of inflammatory T helper cells in multiple sclerosis (MS) patients using vitamin A derivatives (retinoic acids).
Conclusion: The antioxidant activity can be considered as one of the main factors responsible for the neuroprotective effect of antioxidant supplementation. Larger and long-term follow-up studies would be necessary to confirm neuroprotective effects of antioxidant supplementation in MS patients. Such investigation is required for better understanding of the potential of protective effects of antioxidants in cellular immunology of MS neurodegeneration. Not only would that increase our knowledge about the disease mechanisms but also could help to establish new goals for innovative treatment methods and provide real therapeutic benefits in MS.