The effect of propylthiouracil on some physiological parameters of the thyroid gland and histological changes in bone, and the role of aqueous extract of thyme in immature male rats

This study evaluated the physiological and histological effects of Propylthiouracil (PTU) and aqueous extract of Thymus vulgaris on thyroid function and bone growth in albino rats. Thirty males were assigned to six groups: control, thyme (400 mg/kg), PTU (50 mg/kg), PTU (100 mg/kg), thyme + PTU (50 mg/kg), and thyme + PTU (100 mg/kg). Treatments continued for 60 days. Serum analysis demonstrated that PTU induced hypothyroidism, reflected by a significant reduction in T3 (255.4 ± 12.3 pg/ml in control vs. 356.1 ± 15.2 pg/ml in PTU 50 mg; p < 0.05), calcium (10.23 ± 0.44 vs. 8.92 ± 0.38 mg/dl at PTU 50 mg; p < 0.01), vitamin D3 (9.1 ± 0.41 vs. 8.24 ± 0.36 ng/ml at PTU 100 mg), and CT (43.85 ± 1.9 vs. 37.57 ± 1.8 pg/ml at PTU 100 mg). Thyme extract improved endocrine parameters (T3: 294.9 ± 13.2 pg/ml; GH: 470.8 ± 20.5 pg/ml; Ca: 10.28 ± 0.46 mg/dl) and preserved bone microarchitecture. Combined therapy markedly enhanced recovery, with significant restoration of T3 (440.8 ± 18.7 pg/ml at thyme + PTU 50 mg; p < 0.01) and Ca (10.89 ± 0.49 mg/dl at thyme + PTU 100 mg; p < 0.01). Histological evaluation confirmed follicular degeneration and trabecular thinning in the PTU groups, while thyme co-administration mitigated these alterations. Aqueous thyme extract demonstrated significant protective effects against PTU-induced thyroid dysfunction and bone degeneration. These findings highlight thyme as a promising natural therapeutic adjunct for hypothyroidism-associated bone disorders.