The priority of mesenchymal stem cells treated with melatonin in ameliorating thyroid impairment induced by amiodarone. Thorough look on the apoptotic pathway.

Amiodarone treatment has been associated with thyroid alterations. This work was planned to consider therapeutic outcome of MSCs versus MSCs treated with melatonin in minimizing amiodarone -induced deviations in thyroid. We handed-down 50 male Wistar rats, then distributed them into 5 groups; I, II, III, IV, V; control, sham control, amiodarone treated, amiodarone and MSCs treated, and amiodarone, MSCs and melatonin treated groups respectively. Light microscopic examination; levels of T3, T4 and TSH, Oxidative/antioxidative tissue markers, immune-histochemical staining (Bcl2, BAX, iNOS) and real time PCR (IL-6 and VEGF and Caspase 3) were done. Results of group III showed degenerated follicles, decreased follicular cell count and diminished colloid. Some of the follicles were dilated with signs of inflammatory response and apoptosis. Increased collagen deposition in group III was marked. The positive immune-reactive cells of Bcl-2 was decreased and that of BAX and iNOS was increased, also T3 and T4 levels were significantly decreased, but TSH was significantly increased in group III comparing it to the group I. There were highly significant diminution in both SOD and GPx and upsurge in MDA intensities in groups III, IV when correlated to the control. In group IV and V the aforementioned values were restored. The PCR results showed significant increase in IL-6 and VEGF and Caspase 3 in group III compared to the control one, whereas, their values in groups IV and V were reestablished. It is concluded that stem cells can to a great extent ameliorate the thyroid damage induced by amiodarone.But, Adding melatonin to the stem cells culture was found to have auxiliary beneficial effect in the improving the thyroid structure and function.