Clonal Proliferation Of Stem/Progenitor Cells In Different Models Of SD Rat Submandibular Glands

Objective:Established tissue injury models of Sprague-Dawlye (SD) rats with ligation of the main excretory duct, and isoproterenol(IPR) treatment model, we observed the changes of its submandibular glands and compared with the control group. The clonal proliferation ability of stem/progenitor cells of submandibular gland in different models and the activation ability of these models were researched by colony assay. To explore an effective manner of obtaining sufficient stem/progenitor cells of submandibular gland for tissue engineered of salivary glands and stem cell therapy of salivary gland diseases.Methods:Twenty-four male SD rats of 8-weeks-old were randomly divided into three groups, duct ligation group, IPR treatment group and control group. Sections of submandibular gland of each group were used special antibody, such as Ki-67,α6β1,CD90.1,c-kit,Amalyse,Laminin(LN), to immunohistochemistry staining. We analyzed the number of clonal colonies of each group. The immunohistochemistry staining were used to the larger colonies with CD90.1,LN andα6β1,Results:①The positive rate of Ki-67 immunohistochemistry in duct ligation group is the highest, and the IPR treatment group is higher than the normal group(p<0.05). The integral optical density (IOD) of Amylase and LN in duct ligation group is highest, and the IPR treatment group is the lowest(p<0.05). The IOD ofα6β1,CD90.1 and c-kit in duct ligation group is the higher than the other groups(p<0.05).②Colony-forming number was compared in following three different levels based on the number of the colony-forming cells:less than 50 cells,51-100 cells, and more than 101 cells. Colony-forming number for the colonies of each level and the total number were different among the three groups(P< 0.05).③All of the larger colonies cells were positive for CD90.1,LN andα6β1,Conclusion:The highly proliferative cells of submandibular gland which has the characteristics of multipotent stem/progenitor cells. Duct ligation models can effectively activate the stem cells. IPR treatment model is induced hypertrophy and proliferation in acinar cells merely, which cannot increase the number of stem cells, but can enhance the proliferation ability of the stem cells of submandibular gland.