Experiment Study On Tissue Engineering Artificial Salivary Gland

Extreme salivary hypofunction is a common side effect caused by radiation therapy for cancer in the head and neck region. Salivary gland damage leads to persistent hypofunction with marked reduction in salivary output. Unfortunately, at precent, there is no satisfactory treatment for this condition.Tissue engineering combines living cells with a wide range of selected biomaterials, mostly as a substitute for the extracellular matrix or the stroma of the new tissue or organs. In this paper, we developed an salivary gland cells/scaffold construct and implanted it in the bodies of SD rats and nude mouse to evaluate the possibility of building an artificial salivary gland in vitrol.Firstly, we harvested submaridibular gland from neonatal SD rats, after enzymatically digested we subcultured cells that were observed by phase-contrast and electron microscopy. Immunocytochemical analysis of anti-cytokeratin(CK, CK-1 , CK-7, CK-8, CK-14, CK-19), amylase antibody , PAS(periodic acid-schiff) were given and the proliferation curve were evaluated in vitro. After the cultured cells be treated with isoproterenol in different way , the ratio of Brdu (bromodeoxyuridine) labeling positive cells and the growth curve were used to estimate the proliferative ability of the acinar cells. Then we studied the biocompatibility of scaffold. We examined substrata polyglycolic acid (PGA), tracheae of SD rats and rabbits, respectively. The substrata were formed into 5×5mm squares, and the cells were seeded directly onto the PGA or onto the tracheae of rats and ribbats. The morphological characters, cell proliferation (MTT), a-amylase activity in the supematants were detected. The scaffolds without cells incubated also implanted adjacent to skin of cheek and back in mice to study tissue compatibility. At last, we implanted the SSG cells/PGA, SSG cells/tracheae constructs in the bodies of mature SD rats and nude mouse to study the possibility of submandibular salivary gland cells to keep in growth and differentiation as a preliminary step to make an organoid artificial salivary gland.Experiment showed the growth characteristics of submandibular salivary gland cells with increased proliferation. The proliferation and trophism of submandibular salivary gland cells depend on sympathetic and parasympathetic stimulation, and has tight relationship with the concentrations of isoproterenol and methods in use. So we harvested seeding cells for artificial salivary gland. In the biocompatibility study of scaffold, we found acinar cells density on the tracheas of rats and rabbits were higher than on the PGA. Under the scan eletron microscope, the secretory granular could been seen on the cell membrane when salivary epithelial cells were seeded on treachas of rats and rabbits. At last, we implanted submandibular salivary gland cells/scaffolds constructs in the bodies of SD rats and nude mouse, and found the submandibular salivary gland cells in proliferation on the inner surface of the tracheae. The cells incubated on the tracheae expressed strongly positive to anti-amlyase in immunohistochemical staining.Our conclusion is that the results presented here represent an important step toward reconstruction an organoid artificial salivary gland in vivo. With further research, the problems may could be solved in future.