Adipose-derived mesenchymal stem cells regenerate radioiodine-induced salivary gland damage in a murine model

After radioiodine (RI) therapy, patients with thyroid cancer frequently suffer from painful salivary gland (SG) swelling, xerostomia, taste alterations, and oral infections. This study was aimed to determine whether adipose-derived mesenchymal stem cells (AdMSCs) might restore RI-induced SG dysfunction in a murine model. Forty-five mice were divided into three groups; a PBS sham group, a RI+ PBS sham group (0.01 mCi/g mouse, orally), and an RI+AdMSCs (1 x 10(5) cells/150 uL, intraglandular injection on experimental day 28) treated group. At 16 weeks after RI treatment, body weights, SG weight, salivary flow rates (SFRs), and salivary lag times were measured. Morphologic and histologic examinations and immunohistochemistry (IHC) were performed and the activities of amylase and EGF in saliva were also measured. Changes in salivary Tc-99m pertechnetate excretion were followed by SPECT and TUNEL assays were performed. The body and SG weights were similar in the AdMSCs and sham groups. Hematoxylin and eosin staining revealed the AdMSCs group had more mucin-containing acini than the RI group. Furthermore, AdMSCs treatment resulted in tissue remodeling and elevated expressions of epithelial (AQP5) and endothelial (CD31) markers, and increased SFRs. The activities of amylase and EGF were higher in the AdMSCs group than in the RI treated group. Tc-99m pertechnetate excretions were similar in the AdMSCs and sham group. Also, TUNEL positive apoptotic cell numbers were less in the AdMSCs group than in the RI group. Local delivery of AdMSCs might regenerate SG damage induced by RI.