Effects of depression on thyroid function, pathology and ultrasonography in rats

Abstract

To investigate the effects of depression on thyroid function, pathology, and ultrasonography in rats, focusing on inflammatory markers and therapeutic interventions. Depression model rats were randomly divided into three groups: model group, fluoxetine group, and Jingqianshu granules group (10 g/kg/day)—a traditional Chinese medicine with antidepressant and anti-inflammatory effects. Depression was induced through chronic restraint stress. Thyroid function was assessed using serum T3, T4, FT3, FT4, and TSH via ELISA. Immunohistochemistry measured IL-1β, IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ in thyroid tissue. HE staining evaluated histological changes, and ultrasound assessed thyroid echogenicity. The model group showed increased expression of IL-1β, IL-2, IL-6, and TNF-α, and decreased IL-10 and IFN-γ (p < 0.05). Fluoxetine significantly reduced IL-6 (p < 0.05), while Jingqianshu granules notably decreased TNF-α and IL-1β levels (p < 0.05). Thyroid epithelial cells in the model group showed damage, atrophy, and reduced colloid content. Treatment groups showed partial improvement and reduced lymphocyte infiltration. Compared to controls, thyroid echo was significantly diminished in the model group (p < 0.01); treatment groups improved. The model group exhibited elevated FT3 and FT4 levels and reduced TSH, indicating thyroid dysfunction. Both treatment groups showed partial normalization of these hormone levels. Both fluoxetine and Jingqianshu granules alleviated depression-induced thyroid pathological and imaging changes, with Jingqianshu demonstrating partial anti-inflammatory effects and potential as a complementary treatment. Further studies are needed to confirm their efficacy and safety relative to fluoxetine. These findings support further study into depression-related thyroid dysfunction.