Materials and Methods: In the present experimental study, 20 male Balb/C mice were divided into control and hypothyroid groups. The hypothyroid group received 0.05% 6-n-propyl-2-thiouracil (PTU) through drinking water for 35 days. Finally, real-time polymerase chain reaction, immunohistochemistry, periodic acid-Schiff (PAS) staining, terminal transferase-mediated dUTP nick-end labelling (TUNEL) assay, and biochemical measurements were performed after hypothyroidism confirmation.

Results: Laminin α5 and collagen IV mRNA levels were upregulated in the hypothyroid group compared to the controls (P < 0.05). Further, a strong immunoreactivity of collagen IV and laminin α5 was observed in the basement membrane (BM) of hypothyroid mice (P < 0.05). In contrast, there was no significant difference between the case and control groups regarding PAS staining. The number of TUNEL-positive germ cells in hypothyroid mice increased significantly compared to control mice. Moreover, PTU administration reduced superoxide dismutase activity while increasing the malondialdehyde level (P < 0.05). Eventually, no significant difference was found between the two groups in terms of thiol content.

Conclusions: Based on the results of the present study, hypothyroidism can cause changes in BM components and increase the apoptosis of germ cells by inducing lipid peroxidation and reducing the activity of antioxidant defense molecules.