Effects of Silver Nanoparticles on Thyroid Gland Structure and Function in Female Rats

Abstract

Objective: Due to their unique properties, silver nanoparticles (AgNPs) gained a broad utilization in nano-based industries and medicine, which may expose human to increased levels of NPs. However, little is known about their potential harmful effects on endocrine physiology. Hence, this study aimed to investigate the potential dose- and time-dependent outcomes of AgNPs on serum levels of thyroid hormones and thyroid gland histology in female rats.Methods: A total of 60 female rats were divided into three groups (each of 20 animals), treated with AgNPs for (10, 20, and 30) days. Within each treatment period, animals were assigned into four subgroups each of five rats; control treated with vehicle and the others treated with 12.5, 25, and 50 mg/kg of AgNPs, respectively, by intraperitoneal injection. At the end of treatments, all rats were sacrificed; blood samples were obtained and analyzed for serum levels of T3, T4, and thyroid-stimulating hormone (TSH). Thyroid gland was removed and weighed then kept in buffered formalin solution for microscopic examination.Results: The data showed a significant increase in the weight of the thyroid gland after 20 and 30 days of the treatment with 50 mg/kg of AgNPs, while the 25 mg/kg dose of AgNps resulted in significant increase only after 30 days. Serum levels of T3 and TSH were nonsignificantly altered by AgNPs in all the treatment groups. Thyroxin levels (T4) were significantly decreased after long-term exposure. Histological specimens of AgNPs treated group showed disturbance of the normal architecture of the thyroid tissue with degeneration of thyroid follicles and desquamated luminal cells.Conclusion: The results of the current study suggested the possible disrupting potential of long-term exposure to high level of AgNPs on thyroid gland function and histology in female rats.

Synthesis of Silver Nano-particles by Electrochemical Method and the Effects on the Serum Levels of Thyroid Hormones (T3, T4) in Adult Male Rats

“…However, there was no significant difference in the mean serum levels of T4 hormone in all experimental groups compared to that for the control group. The results of this study were partly consistent with those reported by previous studies (18)(19)(20)(21).…”

“…At the completion of the experimental period, animals were anesthetized by ether, and blood samples were collected from the left ventricle of their heart, and centrifuged at 5000 rpm for 15 minutes. The blood sera were collected and used for the measurement ofT3 and T4 hormones by radioimmunoassay (18).…”

Combined lead and zinc oxide‐nanoparticles induced thyroid toxicity through 8‐OHdG oxidative stress‐mediated inflammation, apoptosis, and Nrf2 activation in rats

“…The histopathological study results reported degenerative changes, marked congestion, vacuolation, and inflammatory infiltrates in thyroid tissues of lead, ZnO‐NPs and lead +ZnO‐NPs groups when compared to control groups with marked disruptive changes were observed in the combined group. The results of previous studies reported disruptive structural changes in thyroid tissues by the effect of lead acetate as widening of connective tissues and degeneration of follicular cells, 47 other studies reported distinct histological changes in thyroid tissues, like degeneration of follicles and depletion of colloid materials by the effect of nanomaterials 102 and attributed the structural damage to the ability of absorbed lead and NPs to circulate with the blood and accumulate in different tissues 47 …”