A Histological Study on the Effect of Diclofenac Sodium (Declophen) Administration on Thyroid Follicular Cells of Albino Rats

Introduction: Diclofenac Sodium (declophen) is a nonsteroidal anti-inflammatory drug recently categorized as thyroid antagonist. Aim of the Work: To determine the histo-physiological changes that might occur in the thyroid follicular cells after declophen administration and evaluate their reversibility. Materials and Methods: Thirty adult male albino rats were randomly divided into three groups; Group I (Control group), Group II received declophen (8 mg/kg /day) for one week then sacrificed. Group III received declophen as group II and then sacrificed one week after drug withdrawal. Blood samples were collected to estimate T3, T4 and TSH. Thyroid glands were processed for microscopic examination. Mean follicular diameter and mean height of thyrocytes were morphometerically evaluated and statistically analyzed. Results: Declophen significantly decreased T3 level which did not return back to normal in group III. Histologically, group II showed considerable light microscopic changes as focal distension of follicles that were lined with flattened epithelium. Their colloid revealed minimal peripheral vacuolations. Some follicles showed shedded epithelial lining. Others appeared irregular with disrupted epithelium. That epithelium had irregular dark pyknotic nuclei and vacuolated cytoplasm. Some follicles had apparently little colloid. Ultrastructural changes included dilated rER with electron lucid material and many darkly stained lysosomes. Group III showed some changes compared with Control. Statistically, mean follicular diameter of group II increased significantly while mean epithelial height decreased significantly compared to Control. Group III revealed neither significant increase in mean follicular diameter or decrease in epithelial height in comparison with the control. Conclusion: Declophen has toxic effect on the thyroid follicular cells which was incompletely recovered. So it should be discontinued prior to evaluation of thyroid functions.