Propylthiouracil-induced hypothyroidism protects ionizing radiation-induced multiple organ damage in rats

Abstract

The objective of this study was to examine the potential radioprotective properties of propylthiouracil (PTU)-induced hypothyroidism against oxidative organ damage induced by irradiation. Sprague-Dawley rats were pretreated with saline or PTU (10 mg/kg i.p.) for 15 days, and were then exposed to whole-body irradiation (800 cGy). A group of rats were decapitated at 6 h after exposure to irradiation, while another group was followed for 72 h after irradiation, during which saline or PTU injections were repeated once daily. Lung, liver, kidney and ileum samples were obtained for the determination of malondialdehyde (MDA; an index of lipid peroxidation) and glutathione (GSH, an antioxidant) levels, myeloperoxidase activity (MPO; an index of tissue neutrophil accumulation) and collagen contents, while oxidantinduced DNA fragmentation was evaluated in the ileal tissues. All tissues were also examined microscopically and assayed for the production of reactive oxidants using chemiluminescence (CL). Lactate dehydrogenase (LDH), an indicator of tissue damage, and tumour necrosis factor-(TNF ) were assayed in serum samples. Irradiation caused a significant decrease in GSH level, which was accompanied by significant increases in MDA levels, MPO activity, CL levels and collagen content of the tissues studied (P<0·05-0·001). Similarly, serum TNF and LDH were elevated in the irradiated rats as compared with the control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Our results suggested that PTU-induced hypothyroidism reduces oxidative damage in the lung, hepatic, renal and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.

Effect of Iron, Zinc, Vitamin E and Vitamin C Supplementation on Thyroid Hormones in Rats with Hypothyroidism

“…In the present study, PTU exposed rats showed hypothyroidism which was evidenced biochemically by significant (P<0.05) decrease in serum T3 and T4 levels with significant (P<0.05) increase in serum TSH level as compared to control rats. These results are in agreement with Sener et al (2006) [27] who reported that PTU dramatically reduced thyroid hormones. Serum concentrations of thyroid hormones (T3, T4) and TSH are commonly used as reliable indicators of the thyroid function in humans and experimental animals [42].…”

“…B.W./day (1 ml/250 g) by i.p. injection for 15 day according to Sener et al (2006) [27]. Blood was collected and the serum was separated to measure T3, T4 and TSH.…”

Effect of Selenium and Zinc Supplementation on Hypothyroidism in Rats

“…The mechanism for this response is an increase in TSH levels due to a decrease in the production of thyroid hormone FT4, FT3 (Sener, et al, 2006). This was evidenced biochemically by reduction in serum thyroid hormone levels of FT4, FT3, TT3 and TT4 with increase in serum TSH level compared to the normal control rats.…”

The effect of magnesium and vitamin E pre-treatments on irradiation-induced oxidative injury of cardiac and pulmonary tissues in rats: a randomized experimental study

“…However, whether this reduction of neutrophil accumulation may have an anti-oxidant effect or may decrease the generation of lipid peroxidation is not observed in the present study, because at the 24-h of irradiation neither lung nor cardiac tissue demonstrated any irradiation-induced lipid peroxidation. Since IR-induced injury becomes evident at the 72 nd h of irradiation (37), it is expected that this neutrophil-limiting effect of Mg could have a therapeutic value in the long term.…”