Intraglandular Transplantation of Adipose-Derived Stem Cells for the Alleviation of Irradiation-Induced Parotid Gland Damage in Miniature Pigs.

PURPOSE: In a previous study, the authors verified the protective efficacy of adipose-derived stem cells (ADSCs) on the prevention of salivary gland (SG) damage induced by irradiation in mice. As a critical step before implementation in clinical practice, the present study investigated the protective effect of ADSCs in a miniature pig SG model, because miniature pigs share many characteristics with humans.

MATERIALS AND METHODS: Third-passage autologous ADSCs at a concentration of 4 × 10(6) cells/mL were transplanted by intraglandular injection into parotid glands (PGs) immediately after local irradiation at a single dose of 20 Gy. The injection process was repeated twice a week for 6 consecutive weeks. At 12 weeks after irradiation, functional and histologic evaluations were performed by measuring salivary flow rate (SFR) and hematoxylin and eosin and periodic acid-Schiff staining. Immunohistochemical and transmission electron microscopic examinations also were conducted to evaluate amylase (AMY) production, microvessel density (MVD), and microstructural changes.

RESULTS: The irradiated PGs showed remarkable decreases in SFR, AMY production, and MVD. However, transplantation of ADSCs alleviated irradiated PG morphology and function by preserving more functional acinar cells and increasing SFR and AMY production. In addition, greater MVD was observed in the ADSC-treated group than in the irradiated group.

CONCLUSIONS: These results indicated that intraglandular transplantation of autologous ADSCs is an effective method to protect PGs against damage from irradiation in miniature pigs, which might have clinic application in the future.