A Histological Study of Pathological Changes in the Rat Thyroid Gland Induced by Chronic Ultraviolet-A (UVA) Radiation Exposure According to Exposure Duration

Fatimah M. Qabeeli; Sumaya A. Alusta; Khaldon A. Alssarat; Lutfi T.Faffu

Authors

Fatimah M. Qabeeli Department of Physics, Faculty of Arts and Sciences, Msallata, Elmergib University, Libya. Author
Sumaya A. Alusta Department of Physical Therapy, Faculty of Health Sciences, Al-Ajilat, University of Zawia, Libya Author
Khaldon A. Alssarat Department of Therapeutic Nutrition, Faculty of Health Sciences, Al-Ajilat, University of Zawia, Libya Author
Lutfi T.Faffu Department of Physical Therapy, Faculty of Health Sciences, Al-Ajilat, University of Zawia, Libya Author

Keywords:

Ultraviolet-A radiation, Thyroid histopathology, Oxidative stress, Endocrine disruption, Albino rat model, Photo biological toxicity

Abstract

The thyroid gland is one of the most important endocrine glands responsible for regulating metabolism, growth, and physiological homeostasis in the body. With the increasing exposure to ultraviolet-A (UVA) radiation, growing attention has been directed toward investigating its potential effects on biological tissues.

Aim of the Study:This study aimed to evaluate the histological effects induced by ultraviolet-A (UVA) radiation exposure on the follicular structure of the thyroid gland in adult albino rats and to investigate the relationship between these effects and the duration of exposure.

Materials and Methods: Twenty adult male albino rats were equally divided into four groups: Group I: Control group. Group II: Exposed to ultraviolet radiation for 10 consecutive days at a rate of 8 hours daily. Group III: Exposed to ultraviolet radiation for 15 consecutive days at a rate of 8 hours daily. Group IV: Exposed to ultraviolet radiation for 25 consecutive days at a rate of 8 hours daily. At the end of the experiment, the thyroid glands were excised, and tissue specimens were prepared for histological examination using hematoxylin and eosin staining.

Results: The histological examination of the thyroid glands revealed progressive structural alterations in the exposed groups compared to the control group. These changes included disruption of follicular architecture, variation in follicular size, vascular congestion, reduction of colloid content, epithelial cell crowding, and morphological alterations in epithelial cell shape. The severity of these changes increased progressively with longer exposure duration, being most pronounced in the 25-day exposure group.

Conclusion: The findings indicate that chronic exposure to ultraviolet-A (UVA) radiation induces cumulative harmful histological effects on the thyroid gland, with severity increasing in proportion to exposure duration, which may adversely affect its functional efficiency.

Downloads

Download data is not yet available.

References

1. Alusta, S., Badra, M., & Alsokni, S. (2026). Studying the effect of ultraviolet C radiation on the fine structure of rat skin tissue and blood analysis using transmission electron microscopy. Comprehensive Journal of Science, 10(39), 3977–3988.

2. El-Habit, O. H., Saada, H. N., Azab, K. S., Abdel-Rahman, M., & El-Malah, D. F. (2000). Beta-carotene effect on gamma radiation-induced oxidative stress and genotoxicity in rats. Mutation Research, 466(2), 179–186.

3. Green, L. M., Patel, Z., Murray, D. K., et al. (2002). Cytoskeletal changes in thyroid tissue exposed to gamma radiation. Journal of Radiation Research, 43(3), 213–218.

4. Gutteridge, J. M. C., & Halliwell, B. (1990). Lipid peroxidation in biological systems. Trends in Biochemical Sciences, 15(4), 129–132.

5. Halliwell, B., & Chirico, S. (1993). Lipid peroxidation: Its mechanism and significance. The American Journal of Clinical Nutrition, 57(5), 715S–724S.

6. Karampasi, C., Sfiniadakis, I., Petri, A., & Rallis, M. (2025). Dermatological effects of acute and long-term UV-C exposure: An in vivo study using a portable mercury lamp. Photochemical & Photobiological Sciences.

7. Larsen, P. R., Terry, F. D., & Hall, D. H. (1998). The thyroid gland. In J. D. Wilson (Ed.), Williams textbook of endocrinology (9th ed.). Saunders.

8. McKenzie, R., Björn, L., Bais, A., & Ilyas, M. (2003). Changes in biologically active ultraviolet radiation reaching the Earth’s surface. Photochemical & Photobiological Sciences.

9. Melnikova, V. O., & Ananthaswamy, H. N. (2005). Cellular and molecular events leading to the development of skin cancer. Mutation Research, 571(1–2), 91–106.

10. Nadol’nik, L. I., Netsetskaia, Z. V., & Vinogradov, V. V. (2003). Effects of gamma irradiation on rat thyroid status. Radiation Biology and Radioecology, 43, 65–70.

11. Nadol’nik, L. I., Netsetskaia, Z. V., Kardash, N. A., et al. (2004). Functional and morphological changes of rat thyroid gland after radiation exposure. Radiation Biology and Radioecology, 44, 535–543.

12. Osipov, A. N., et al. (2022). The damaging effects of long UVA (UVA1) rays: A major challenge to preserve skin health and integrity. International Journal of Molecular Sciences, 23(15), Article 8243.

13. Ravindran, J., Indrajith, A., Pratheesh, K. P., Sanjiviraja, C., & Balakrishnan, V. (2010). Ultraviolet radiation-induced biological effects. Journal of Environmental Biology.

14. Somosy, Z. (2000). Radiation response of cell organelles. Micron, 31(2), 165–181.

15. Turker, H. (2004). Effect of ultraviolet radiation on thyroid hormones in mole rat (Spalax leucodon). GU Journal of Science, 17, 1–8.

16. Tyrrell, R. M. (2011). Modulation of gene expression by oxidative stress generated in human skin cells by UVA radiation. Photochemical & Photobiological Sciences, 10(2), 199–206.