title: Intraglandular transplantation of bone marrow-derived clonal mesenchymal stem cells for amelioration of post-irradiation salivary gland damage.
abstract: OBJECTIVE
  External irradiation in head and neck cancers may induce irreversible hyposalivation and consequent xerostomia, stemming from radiation damage to salivary glands (SGs). As cell-based therapy has been reported to be able to repair or restore damaged SG tissues, we attempted to determine whether bone marrow-derived clonal mesenchymal stem cells (BM-cMSCs) can ameliorate irradiation-induced salivary gland damage via a murine model.
  
  
  METHODS
  External irradiation at a dose of 15Gy was delivered to the neck fields of C57BL/6 mice. We directly administered either homologous mouse BM-cMSCs labeled with PKH26 (treatment group) or PBS (control group) into SGs 24h after irradiation. Salivary flow rate (SFR) and lag time of salivation were measured at 12weeks after transplantation. At 4 and 12weeks post-transplantation, we performed morphological, histological, and immunofluorescent examinations. Transdifferentiation of administered BM-cMSCs into salivary epithelial cells was observed by confocal microscopy.
  
  
  RESULTS
  SFR was significantly increased in BM-cMSCs-transplanted mice compared with PBS-injected mice at 12weeks after transplantation. Administration of BM-cMSCs preserved the microscopic morphologies of SGs, with more functional acini in BM-cMSC-transplanted SGs than in PBS-injected SGs. Immunofluorescent staining revealed less apoptotic cells and increased microvessel density in BM-cMSC-transplanted SGs compared with PBS-injected SGs. PKH-26 labeled BM-cMSCs were detected in transplanted SGs at 4weeks after transplantation and in vivo transdifferentiation of BM-cMSCs into acinar cells was also observed.
  
  
  CONCLUSIONS
  This study suggests that BM-cMSCs can ameliorate salivary damage following irradiation and can be used as a source of cell-based therapy for restoration of irradiation-induced salivary hypofunction.
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Inha University School of Medicine, Incheon, Republic of Korea.
authors.forename: Jae-Yol
authors.initials: JY
authors.lastname: Lim
authors.forename: Tacghee
authors.initials: T
authors.lastname: Yi
authors.forename: Jeong-Seok
authors.initials: JS
authors.lastname: Choi
authors.forename: Yun Ho
authors.initials: YH
authors.lastname: Jang
authors.forename: Songyi
authors.initials: S
authors.lastname: Lee
authors.forename: Hun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sun U
authors.initials: SU
authors.lastname: Song
authors.forename: Young-Mo
authors.initials: YM
authors.lastname: Kim
mesh_terms: D000818:Animals; D001835:Body Weight; D002454:Cell Differentiation; D002470:Cell Survival; D007150:Immunohistochemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D012469:Salivary Glands / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects*; D033581:Stem Cell Transplantation