Introduction: Intermittent fasting is popularity and a promising approach for weight loss by daily restricted eating. Thyroid hormones controls body metabolism and accelerate the basal metabolic rate.
Aim of this Work: was designed to investigate the effect of intermittent fasting alone and when concomitant with levothyroxine on the histological characterization of the thyroid gland of the adult male albino rats.
Material and Methods: Twenty-four adult male albino rats were used and randomly divided into four equal groups. Group I (Control): Rats had free access to food and water. Group II (Fasting): Rats were deprived of food for 16 hrs daily with free access to water all over the day. Group III (levothyroxine): Each rat received levothyroxine (0.5μg/100g body weight /day) for three successive weeks via gastric tube and rats had free access to food and water all over the day. Group IV (Fasting +levothyroxine): Each rat received daily levothyroxine as in group III combined with food deprivation as in group II. At the end of the experiment, rats were sacrificed, and the thyroid glands were immediately obtained. The tissue samples were processed for paraffin and epon blocks. Thyroid sections were subjected to H&E, toluidine blue and Masson's Trichrome. Also, immunohistochemical study was carried out for the detection of apoptosis and parafollicular cells.
Results: The experimental intermittent fasting mildly affected the thyroid gland structure in comparison to the control group. In Levothyroxine treated group, most of follicles showed signs of degeneration in the form of their lining appeared vacuolated with dark nuclei and small or micro-follicles. While, fasting with levothyroxine showed marked obvious changes, flattened follicular cells with dark nuclei and vacuolated cytoplasm, desquamated foamy cells and scanty luminal colloid.
Conclusion: The obtained results revealed marked degenerative changes of thyroid gland when intermittent fasting combined with levothyroxine.