Evaluation of the effect of placental and spleen cryoextracts, and conditioned medium of mesenchymal stem cells, on thyroid hormone synthesis in experimental autoimmune thyroiditis

Background. Thyroid diseases (TD) are the most common endocrine disorders, affecting more than 10% of the adult population. The most prevalent forms of autoimmune thyroid diseases (AITD) are Graves disease and Hashimotos thyroiditis. The standard treatment for hypothyroidism involves restoring thyroid hormone levels to normalize their concentration in tissues. Our attention was drawn to the study of the efficacy of biotechnology drugs that do not contain cells subjected to low-temperature treatment during their production or prolonged storage. Purpose. The aim of the study was to characterize the impact of placental cryoextract (CEP), spleen cryoextract (CES), and conditioned medium of mesenchymal stem cells (MSC-CM), on thyroid hormone synthesis in experimental autoimmune thyroiditis (AIT). Materials and Methods. AIT was modeled by injecting rats with a thyroid antigenic mixture consisting of Freunds complete adjuvant and an antigen solution derived from the homogenate of allogeneic thyroid tissue in a 1:1 ratio. The study was conducted on 42 male rats weighing 200–220 g, randomly assigned to 6 groups. The levels of T3 and T4 were determined on day 28 of the experiment using an enzyme immunoassay (ELISA) method with standard ELISA kits. Results. The study of the impact of L-thyroxine, CEP, CES, and MSC-CM on thyroid hormone levels in rats with AIT showed significant changes in T3 and T4 levels in serum. It was found that in the AIT group, there was a statistically significant (p<0.001) increase in total T3 levels by 72.0% compared to the intact rats. After treatment, different drugs showed varying levels of effect on the hormonal profile. L-thyroxine effectively normalized the levels of free T3 and T4, reducing them by 30.3% (p<0.001) and 30.8% (p<0.001), respectively. The introduction of CEP, CES, and MSC-CM contributed to a reduction in hormone levels to varying degrees. Conclusions. The development of AIT in rats causes disturbances in thyroid hormone metabolism, manifesting as an increase in total and free T3 and T4 levels. All studied biological preparations led to a more pronounced normalization of total T3 levels than L-thyroxine. The highest reduction in total T4 levels occurred with the introduction of CEP, while the greatest reduction in free T4 levels occurred with the administration of MSC-CM.