Impact of Chronic Noise Stress on Thyroid Health: A Comparative Histomorphological and Endocrine Study in Adult Male...

To compare the effect of varying durations of noise exposure on the histomorphological and endocrine profile of the thyroid gland in male and female adult rats.

An experimental study. Place and Duration of the Study: Department of Anatomy, Army Medical College, Rawalpindi / NUMS, from January to December 2020.

Thirty Sprague-Dawley rats (15 males and 15 females) were divided into three groups each having 10 rats with equal male- to-female ratio. Group A was the control group. Group B and Group C were exposed to 100 dB noise for 4 hours daily and 100 dB noise for 6 hours daily for 4 months, respectively. Thyroid histomorphological parameters such as follicular epithelial cells' height, follicular diameter, and thyroid stimulating hormone (TSH) levels were evaluated at the end of the study.

Both male and female rats exposed to noise stress exhibited reduced follicular diameter (p <0.001) and increased epithelial cells' height (p <0.001) as compared to the control group. The experimental groups showed significantly higher TSH levels compared to the control group (p <0.001) among female rats, while no significant difference was observed among male rats (p 0.47). No significant differences in histological and serum parameters were noted between the experimental groups (Group B and C).

Chronic noise exposure induces hyperactivity of thyroid follicles in both male and female adult rats as evidenced by the thyroid histology, whereas only female rats showed raised TSH levels, suggesting a potential disruption in the hypothalamic-pituitary-thyroid axis.

Thyroid gland, Chronic noise stress, Follicular epithelial cells, Thyroid stimulating hormone, Thyroid follicles.