HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY ON THE EFFECT OF SOME ANTIARRHYTHMIC DRUGS ON PARAFOLLICULAR C CELLS IN MALE ALBINO RATS
Rahma Kamal El Din Abu El Nour
Department of Histology, Faculty of Medicine, Cairo University
The aim of this work was to show the effect of some antiarrthymic drugs, amiodarone, propranolol and verapamil on the parafollicular cells using semithin sections and immunohistochemical reaction of calcitonin. Thirty six male albino rats were divided into group I (control group), 2 for each of the experimental groups given poly-sorbate tween 80 and distilled water for the same periods as in the experimental groups. The latter included amiodarone, propranolol and verapamil groups (groups II, III & IV) each consisting of ten rats subdivided into subgroups II A, III A and IV A (each 5 rats) given amiodarone 30 mg/kg, propranolol 2.3 mg/kg and verapamil 3.4 mg/kg respectively orally daily for two month. Subgroups II B, III B and IV B (each 5 rats) were given the drug for two months and were sacrificed one month after cessation of drug (recovery). Thyroid specimens were prepared for semithin sections and immunohistochemical staining for calcitonin. Morphometric assessment of area% and count of calcitonin immunopositive parafollicular cells was performed. Statistical analysis was done. Semithin sections showed follicular cells with vacuolated or ballooned cytoplasm and dark nuclei in amiodarone treated group. In propranolol group multiple follicular cells revealed dark nuclei and cytoplasmic vacuolation. In verapamil group few follicular cells showed dark nuclei and cytoplasmic vacuolation. The findings were less in the corresponding recovery subgroups. Dark nuclei of parafollicular cells were seen in all experimental groups. Immunohistochemical staining of calcitonin appeared in the cytoplasm of multiple C cells in amiodarone group, fewer +ve cells were detected in propranolol and verapamil groups. All corresponding recovery subgroups showed less +ve cells. A significant increase in mean area% and count of calcitonin immunopostive C cells was found in all studied groups when compared to the control even in the recovery subgroups. It could be concluded that C cells proliferation and consequent increased calcitonin production resulted in response to amiodarone, propranolol and verapamil administration and persisted in recovery subgroups, indicating incomplete recovery after one month.