title: Proliferative Activity of Myoepithelial Cells in Irradiated Rabbit Parotid and Submandibular Salivary Glands.
abstract: BACKGROUND
  The behavior of salivary myoepithelial cells (MEC) during chronic irradiation exposure is unknown. This study aimed to investigate the response of MEC to prolonged radiation exposure.
  
  
  METHODS
  16 rabbits and four controls were irradiated with either 10 Gy, 20 Gy, 30 Gy or 40 Gy (Gray units) of direct axial beam radiation. Parotid and submandibular glands were removed and examined using immunohistochemical double staining. Proliferating MEC were semi-quantified using alpha smooth muscle actin antibodies and proliferating cell nuclear antigen (PCNA) antibodies.
  
  
  RESULTS
  MEC proliferative activity increased after radiation in both submandibular (P = 0.037) and parotid groups (P = 0.006) compared to controls. Hyper-proliferation was seen only in parotid glands which was almost dose-dependent. Mean percentage MEC proliferation did not correlate with the clinical grading or recovery from oral mucositis (P = 0.47).
  
  
  CONCLUSIONS
  Parotid glands are more sensitive to radiation compared to submandibular glands. Further research is needed to determine the role of MEC proliferative activity in response to radiation.
authors.affiliation: Assistant Professor, Department of Oral and Maxillofacial Sciences, School of Dentistry, Al-Farabi Colleges, Riyadh, Kingdom of Saudi Arabia ; Assistant Professor, Department of Oral Pathology, School of Dentistry, Hama University, Hama, Syria.
authors.forename: Omar
authors.initials: O
authors.lastname: Kujan
authors.affiliation: PhD Student, Department of Oral Pathology and Histology, School of Dentistry, Damascus University, Damascus, Syria.
authors.forename: Rania
authors.initials: R
authors.lastname: Othman
authors.affiliation: Consultant, Department of Dental, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Alshehri
authors.affiliation: Senior Registrar, Department of Gastrointestinal Physiology, St. Mark's Hospital & Academic Institute, London, UK.
authors.forename: Fareed
authors.initials: F
authors.lastname: Iqbal
authors.affiliation: Associated Professor at Oral Pathology and Histology Department, Faculty of Dentistry, Damascus University and Head of Oral Pathology Department in International University of Science and technology, Damascus, Syria.
authors.forename: Nabil
authors.initials: N
authors.lastname: Kochaji
keywords: Experimental; mucositis; myoepithelial cells; proliferating cell nuclear antigen; salivary