Advances in Antioxidant Applications for Combating 131I Side Effects in Thyroid Cancer Treatment

Abstract

Thyroid cancer is the most common endocrine cancer, and its prevalence has been increasing for decades. Approx. 95% of differentiated thyroid carcinomas are treated using 131iodine (131I), a radionuclide with a half-life of 8 days, to achieve optimal thyroid residual ablation following thyroidectomy. However, while 131I is highly enriched in eliminating thyroid tissue, it can also retain and damage other body parts (salivary glands, liver, etc.) without selectivity, and even trigger salivary gland dysfunction, secondary cancer, and other side effects. A significant amount of data suggests that the primary mechanism for these side effects is the excessive production of reactive oxygen species, causing a severe imbalance of oxidant/antioxidant in the cellular components, resulting in secondary DNA damage and abnormal vascular permeability. Antioxidants are substances that are capable of binding free radicals and reducing or preventing the oxidation of the substrate in a significant way. These compounds can help prevent damage caused by free radicals, which can attack lipids, protein amino acids, polyunsaturated fatty acids, and double bonds of DNA bases. Based on this, the rational utilization of the free radical scavenging function of antioxidants to maximize a reduction in 131I side effects is a promising medical strategy. This review provides an overview of the side effects of 131I, the mechanisms by which 131I causes oxidative stress-mediated damage, and the potential of natural and synthetic antioxidants in ameliorating the side effects of 131I. Finally, the disadvantages of the clinical application of antioxidants and their improving strategies are prospected. Clinicians and nursing staff can use this information to alleviate 131I side effects in the future, both effectively and reasonably.

Effects of postoperative antioxidants on the salivary glands in patients with thyroid cancer undergoing radioactive iodine-131 treatment

“…Acute salivary gland injury is mostly manifested by pain and swelling in the salivary gland area, which often occurs about 48 h to 1 week after 131 I treatment; chronic injury is mostly manifested by excretory dysfunction, such as slowing of salivary flow rate, reduction of salivary volume, oral dysfunction, change of taste, and severe bad breath, which often occurs a few months to 1 year after 131 I treatment. Numerous data suggest that 131 I treatment interferes with redox cellular pathways, resulting in a massive production of reactive oxygen species, leading to a severe intracellular oxidant/peroxidant imbalance, which ultimately leads to secondary DNA damage, vascular permeability abnormalities, and secondary cancers [7–10], whereas antioxidants bind oxygen radicals and thus reduce or prevent the substrate from undergoing oxidation, and thus can be utilized for the reduction or prevention of salivary dysfunction induced by 131 I treatment [11]. Salivary gland damage induced by 131 I treatment.…”

The Protective Effect of Exogenous 17β-Estradiol against Experimentally Induced Oxidative Damage to Membrane Lipids Is Stronger in Male vs. Female Porcine Thyroids: Preliminary Results

“…However, because it is a preliminary one, further research is required with the use of other experimental models, possibly other species, and with the examination of other biological molecules, such as DNA and proteins. As natural anti-oxidants have recently been recommended to eliminate the toxic effects of radioiodine used in the treatment of thyroid cancer [ 29 ], 17β-estradiol should be considered as a prominent candidate applied in studies on protection against the damaging effects caused by radioiodine or by other kinds of treatment. However, taking into account the potential pro-oxidative, and, therefore, unfavorable, action of 17β-estradiol, its simultaneous application with other anti-oxidants should be considered in future studies, especially since a cumulative protective effect of two anti-oxidant indole substance has recently been observed in the thyroid gland [ 30 ].…”