MORPHOLOGICAL FEATURES OF THE THYROID GLAND AFTER CHEMICAL BURNS OF THE DIGESTIVE TRACT AND THEIR CORRECTION UNDER EXPERIMENTAL CONDITIONS

Abstract

Chemical burns of the digestive tract are severe pathological conditions that trigger not only local tissue injury but also systemic metabolic, inflammatory, and endocrine disturbances. Among endocrine organs, the thyroid gland is particularly sensitive to generalized stress and toxic injury because of its high vascularization, active protein synthesis, and close involvement in metabolic regulation. The present study was aimed at investigating the morphological and histochemical changes in the thyroid gland after experimental chemical burns of the digestive tract and evaluating the structural trends observed during correction. The investigation was carried out on white outbred rats, and thyroid tissue was examined using routine histological assessment with Van Gieson staining. The analysis focused on follicular architecture, colloid characteristics, the condition of follicular epithelium, stromal connective tissue, and the microcirculatory bed. The control group demonstrated preserved follicular organization, homogeneous colloid, cuboidal thyrocytes, and a delicate stromal framework, corresponding to a stable euthyroid structural pattern. After chemical injury, the thyroid gland showed follicular polymorphism, uneven colloid distribution, resorption phenomena, increased epithelial height, stromal thickening, and vascular congestion, indicating functional strain and the development of early pathological remodeling. In animals subjected to correction, the thyroid gland displayed partial restoration of follicular organization, improved colloid homogeneity, reduced epithelial hyperactivity, and attenuation of stromal and microvascular disturbances. The findings indicate that chemical burns of the digestive tract induce substantial morphofunctional alterations in the thyroid gland, whereas corrective intervention contributes to structural stabilization, although full normalization may not occur at the studied stage. The study supports the view that the thyroid gland may serve as a sensitive morphological marker of systemic injury and of the effectiveness of therapeutic correction