Effect of broccoli sprouts on thyroid function, haematological, biochemical, and immunological parameters in rats with thyroid imbalance

Broccoli sprouts may exert a negative influence on thyroid function as they are a rich source of glucosinolates, in particular glucoraphanin. Under the study in a long-term experiment broccoli sprouts were tested as an element of rats diet, combined with deficient iodine, or sulfadimethoxine ingestion -two models of hypothyroidism. Evaluations were performed for serum TSH and thyroid hormones completed with analyzes of selected haematological, biochemical and immunological (IL-6, IL-10) parameters, as well as cytosolic glutathione peroxidase (GPX1), thioredoxin reductase (TR) in the thyroid, and plasma glutathione peroxidase (GPX3). A thermographic analysis was conducted to provide auxiliary indicators for determining a potential thyroid dysfunction under the specific experimental conditions. The levels of TSH, fT3 and fT4 remained unchanged following broccoli sprouts ingestion, which was even found to have a protective effect against sulfadimethoxine induced thyroid damage. Moreover, TR activity significantly increased in response to sprouts ingestion. In animals with hypothyroidism, broccoli sprouts were found to exert a beneficial influence on the antioxidant balance of the thyroid gland. In comparison to the rats with iodine deficiency, broccoli sprouts addition to the diet was observed to decrease IL-6 level. No significant differences in IL-10 concentration were determined. Neither addition of broccoli sprouts to the diet, nor sulfadimethoxine and iodine deficiency, caused negative changes in red blood cell parameters, glucose and uric acid concentrations, or kidney function. However, such a dietary intervention resulted in reduced WBC and PLT levels, and it may adversely interfere with liver function in rats, most likely due to a higher dietary intake of glucosinolates.