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Updated: May 9, 2025
Retroductal Submandibular Gland Instillation and Localized Fractionated Irradiation in a Rat Model of Salivary Hypofunction
Published on: April 24, 2016
Long-Term Regenerative Potential of Submandibular Glands in Albino Rats Following Radiotherapy: Role of Cytokeratin
Sherif S Hassan1,2, Mashael Alqahtani2
1Department of Oral Biology, Faculty of Dentistry, Al Azhar University, Cairo, EGY.
Background:
Fractionated radiotherapy (RT) is a common approach for treating head and neck malignancies in which the salivary glands become included within the radiation field, causing xerostomia. This study aimed to evaluate the long-term effects of post-dose RT to determine the possibility of recovery of the submandibular gland (SMG) without intervention or further deterioration.
Methods:
Twenty-seven albino rats were divided into three equal groups, each containing nine rats. The first group is the control group, which was not exposed to radiation. The second and third groups served as the experimental groups, receiving a total radiation dose of 30 Gy, divided into 5 Gy doses per day over six consecutive days. The SMGs were extracted and prepared for histopathological and immunohistochemical analysis, one month after irradiation for Group II and one year after irradiation for Group III.
Results:
Immunohistochemical analysis of the control salivary gland revealed weak to mild staining for cytokeratin 17 (CK17) (intermediate filaments) in the cells of the duct system and serous acinar cells. The irradiated SMG exhibited significantly moderate to strong cytokeratin expressions in the duct cells (P=0.000 for Group II and P=0.025 for Group III) compared with the control. In contrast, the serous acinar cells in Group II exhibited significantly increased immunostaining for cellular keratin (P = 0.001) compared to the control group. Meanwhile, the acinar cells in Group III showed CK17 expression levels similar to those observed in the control group (P = 0.297).
Conclusion:
CK17 expression differed significantly between the control and the second group, which underwent a one-month wait after the final radiation dose. In contrast, the third group, which underwent a one-year wait, showed intermediate results between the two groups, indicating a more advanced stage of recovery. Statistical analysis showed differing recovery dynamics, with ductal cells exhibiting slower recovery than acinar cells, which appeared more advanced in their healing. These findings highlight the progressive yet varied repair processes within the irradiated glands.
