Expression of ADAMTS2 and ADAMTS5 in the salivary gland of rats after radioiodine therapy

Effect of selenium on the dysfunction of rat salivary glands induced by 131I and expression of insulin-like growth factors and aquaporins

OBJECTIVES

To investigate the effects of selenium on functional and histopathological changes and mRNA expression levels of insulin-like growth factors 1 and 2 (IGF-1 and -2) and aquaporins 4 and 5 (AQP-4 and -5) in 131 I-induced damaged rat parotid glands.

METHODS

Rats were divided into three groups: iodotherapy-with-selenium, iodotherapy-only, and control. Rats in the iodotherapy-with-selenium group were intragastrically administered 131 I on the first day and selenomethionine through drinking water. Rats in the iodotherapy-only group were only administered 131 I. Changes in parotid gland function were evaluated using the functional parameters of salivary gland dynamics imaging pre-experiment and on days 7, 30, and 90 post-treatment. Immunofluorescence and quantitative real-time PCR analyses detected IGF-1, IGF-2, AQP-4, and AQP-5 expression levels in tissues.

RESULTS

The gland-to background ratio at a maximum count (G/BG max ), T max /T min , and S max values were significantly impacted over time in the iodotherapy-with-selenium group; on day 30, the G/BG max value was significantly higher than that in the iodotherapy-only group. Histopathological analysis revealed that on days 30 and 90, the iodotherapy-with-selenium group displayed greater parotid gland repair than the iodotherapy-only group. In the iodotherapy-with-selenium group, fluorescence intensity and mRNA levels of AQP-5 increased with the selenium supplementation period, reaching significantly higher levels on days 30 and 90 than in the iodotherapy-only group. Whereas the fluorescence intensity and mRNA levels of IGF-1 in the iodotherapy-with-selenium group were significantly higher on day 7 than on day 30 in the iodotherapy-only group.

CONCLUSION

Selenium may repair 131 I-induced tissue and functional damage in rat salivary glands by upregulating AQP-5 and IGF-1 expression.

Sialadenitis as a complication of radioiodine therapy in patients with thyroid cancer: where do we stand?

PURPOSE

This study aims to elaborate on the current knowledge concerning the mechanism, frequency, clinical manifestations, diagnostic procedures, prevention, and management of radioactive iodine (RAI)-induced sialadenitis in patients receiving treatment for differentiated thyroid cancer (DTC).

METHODS

A review of the literature was carried out through the " www.ncbi.nlm.nih.gov/pubmed " database focusing on the results of the past decade.

RESULTS

The high concentration of RAI in the salivary glands results in high beta radiation exposure of the striated duct cells and stem cells. This exposure leads to acute and/or chronic sialadenitis with obstructive symptoms and progressive loss of salivary gland function and xerostomia, with severe impact on patients' quality of life. No standard diagnostic method has been established. As far as prevention is concerned, many approaches have been proposed, such as sialogogues, local massage, vitamin E, and amifostine administration. Although there is no unanimity as to their effectiveness, the use of sialogogues is recommended. Treatment includes conservative drug therapy and sialendoscopy when necessary.

CONCLUSION

RAI-induced sialadenitis has a major impact on patients' quality of life. Due to the good prognosis of DTC, the reduction of sialadenitis and its prognosis, prevention, and treatment constitute a priority for the overall treatment of these patients. Further studies that will establish a coherent treatment protocol for this condition are necessary.

Experimental Animal Model Systems for Understanding Salivary Secretory Disorders

Salivary secretory disorders are life-disrupting pathologic conditions with a high prevalence, especially in the geriatric population. Both patients and clinicians frequently feel helpless and get frustrated by the currently available therapeutic strategies, which consist mainly of palliative managements. Accordingly, to unravel the underlying mechanisms and to develop effective and curative strategies, several animal models have been developed and introduced. Experimental findings from these models have contributed to answer biological and biomedical questions. This review aims to provide various methodological considerations used for the examination of pathological fundamentals in salivary disorders using animal models and to summarize the obtained findings. The information provided in this review could provide plausible solutions for overcoming salivary disorders and also suggest purpose-specific experimental animal systems.