Neonatal exposure to T3 disrupts male reproductive functions by altering redox homeostasis in immature testis of rats

Abstract

T3 is the active hormone, produced by peripheral deiodination of thyroxine. Exposure to excess thyroid hormones leads to hypermetabolic state and thus generates oxidative stress which seems to be involved in hyperthyroidism-induced testicular pathophysiology. We investigated the effects of T3 administration on the testis during development throughout sexual maturation in rats. Male pups were divided into two groups. T3 group was administered 80 µg/kg body weight intraperitoneal T3 injections daily for 21 days from the 1st postnatal day, while the control group was administered saline intraperitoneal injections. The pups were sacrificed at pnd 10, 20 and 30. T3 treatment resulted in a significant decrease in body weight at all ages tested and an increase in testis weight during the treatment period. The treatment produced imbalance in their testicular redox status, reflected by a significant increase in the amount of thiobarbituric acid-reactive substances and protein carbonyl content in the testicular homogenates of 20-day-old rats. We observed a significant increase in antioxidant system activities γ-glutamyl transferase, glucose-6-phosphate dehydrogenase, catalase and superoxide dismutase, reduced glutathione content and lactate dehydrogenase activity. Histological examination showed altered seminiferous tubules, degenerated germ cells and decreased height of the germinal epithelium. Chronic neonatal exposure to T3 resulted in redox state alterations which contribute to testicular impairment.

Hypothyroidism: morphological and metabolic changes in the testis of adult albino rat and the amelioration by alpha-lipoic acid

“…Thyroid hormones have a well-known physiological role in modulating the process of oxidative stress caused by reactive oxygen species [28]. Its deficiency is known to induce hypothyroidism and oxidative stress and perhaps might lead to testicular dysfunction and infertility [20]. In males, hypothyroidism is accompanied by hypogonadism and other abnormalities, like a declined serum testosterone [24].…”

Markers of Lipid and Protein Oxidation in the Blood of Women and Men With Autoimmune Hashimoto's Thyroiditis

“…Significant increases in the amount of TBARS or lipid hydroperoxides were observed in the testicles of hyperthyroid adult rats (Zamoner et al, 2007). The T3 treatment produced an imbalance in their testicular redox status, reflected by a significant increase in the amount of TBARS and protein carbonyl content in the testicular homogenates of 20-day-old rats (Kamel and Hamouli-Said, 2018). Cheserek et al (2015) determined whether there was increased oxidation of lipids and proteins in SCH, and examined their association with lipids and thyroid hormones.…”

Selenium protects against nesfatin‐1 modulation of the hypothalamic‐pituitary‐testicular axis during hypothyroidism in male rats

“…Research has proven that a lack of thyroid hormone can trigger not only hypothyroidism but also oxidative stress, and regression of fertility and testicular function (Kamel & Hamouli‐Said, 2018 ). In men, hypothyroidism is associated with hypogonadism (Krysiak et al., 2020 ).…”