Print ISSN 2537-0308 • Online ISSN 2537-0316 ADJ-for Girls, Vol. 7, No. 1, January (2020) — PP. 31: 39 The Official Publication of The Faculty of Dental Medicine For Girls, Al-Azhar University Cairo, Egypt. AL-AZHAR Dental Journal F o r G i r l s ABSTRACT Purpose: the objective of the present study was to evaluate the effect of BM-MSCs on irradiated submandibular salivary glands in mice and to determine at which stage post-irradiation the cells should be transplanted. Materials and methods: 58 adult male mice were used, 10 for preparation of PKH-26-labeled BM-MSCs and the re- maining 48 mice were divided into: control group (GӀ) consisted of 6 mice without radiation and experimental groups consisted of 42 mice irradiated with a single dose of 15Gy. They were randomly divided into three groups: GӀӀ (+ve control): 18 irradiated not treated mice and two treated groups each consisted of 12 irradiated mice and treated with intraglandular injection of labeled BM-MSCs, 24 hours (GӀӀӀ) and at day 11 (GΙV) post-radiation. Animals were sacrifced at day 6, day 30 and day 90 post-radiation. The submandibular glands were collected, one gland was routinely prepared for histological examination using H&E staining and the other was prepared for immunohistochemical study using immunofuorescence staining with anti- α-amylase 1 antibody. Results: BM-MSCs produced marked improvement in salivary gland tissue architecture, histol- ogy of parenchymatous and stromal structures and glands function indicated by marked increase in α amylase 1 production compared with +ve control group, with GӀӀӀ showed greater improvement than GΙV. Conclusions: It could be concluded that: intraglan- dular transplantation of BM-MSCs could successfully regenerate radiation-induced submandibular salivary gland damage and restore the gland function. The early trans- plantation of BM-MSCs 24 hours post-radiation was markedly more benefcial than the transplantation at day 11 post-radiation. Codex : 05/2001 azhardentj@azhar.edu.eg http://adjg.journals.ekb.eg DOI: 10.21608/adjg.2019.7619.1099 KEYWORDS BM-MSCs, submandibular salivary glands, radiation, immunofuorescence, anti- α- amylase 1. • Paper extracted from Doctor thesis titled (Stem Cells and Their Potential Effect on Irradiated Submandibular Salivary Glands in Mice). 1. Assistant Lecturer of Oral and Dental Biology, Faculty of Dental Medicine for Girls, Al-Azhar University. 2. Professor of Oral and Dental Biology, Former Dean of the Faculty of Dental Medicine for Girls, Al-Azhar University. 3. Professor of Oral and Dental Biology, Faculty of Dentistry, Cairo University. 4. Assistant Professor of Biochemistry, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority, Cairo. *Corresponding author Email: sehamhallool@gmail.com Stem Cells and Their Potential Effect on Irradiated Submandibular Salivary Glands in Mice Seham I. Hallool 1* , Mona H. Farid 2 , Samah S. Mehanny 3 , Hanan F. Abdel Hamid 4