Evaluation of the Cell Death Pathway and Apoptosis-Stunning Effect Relationship After Low- and High-Dose I-131 Administrations in Rat Thyroid Tissue

Abstract

Following I-131 administration, two types of cell death--both apoptosis and necrosis findings--have been observed in most of the rats. We think that the decreased uptake values are because of the probable stunning effect in thyroid tissue. We also investigated whether the stunning effect is related to apoptosis. According to our results, it can be concluded that the stunning effect is not related to tissue damage, cell decrease, or cell death. Alternatively, we think that this can be related to a radiation-induced reduction of iodine uptake/metabolism or a modified iodine transport mechanism. For further in vivo studies, this experimental model using normal rat thyroid tissue may be useful in investigating the cell death pathways induced by I-131 and its probable roles in the development of the stunning phenomenon.

Therapy of large multinodular goitre using repeated doses of radioiodine

“…This tendency may be attributed to two factors: (i) gradual decrease of the number of functioning thyroid cells after each consecutive course of RIT and (ii) the thyroid stunning effect. The latter effect is explained by a downregulation of NIS and apoptosis of the thyroid cells [32,33].…”

The alteration of asymmetric dimetilarginine (ADMA) levels in cardiac and gastrocnemius muscles following radioactive iodine application in guinea pigs and the effect of L-carnitine on this alteration

“…Despite that experimental models on acute or chronic side-effects of the RAI treatment are limited (Fregly et al 1960, Fortier and Schindler 1962, Turgut et al 2006a, 2006b), a single high dose radioactive I-131 ablation therapy model in guinea pig was chosen in the present study. Guinea pigs in RAI groups received 30 mCi/kg body weight (dose limits: 15-18 mCi) I-131 intraperitoneally (i.p.)…”