Objective: To study the cell proliferation in endolymphatic sac(ES) during the secondary immune response in inner ear.
Methods: Fifteen healthy, female SD rats were employed in the experiment. Sensitized systematically with keyhole limpet hemocyanin (KLH), the animals were inoculated with the same antigen through cochlea basal turn into the labyrinth. Administrated 5-bromo-2'-deoxyuridine (BrdUrd) intraperitoneally, the rats were sacrificed and the temporal bones were harvested at 3, 7, 14 day after labyrinth vaccination respectively. The frozen sections of the decalcified samples were dealt with H-E staining and immunohistochemical methods to investigate the cellular infiltration, BrdUrd and IgG positive cells in the ES.
Results: While the ES lumen and perisaccular region were infiltrated with mononuclear-phagocyte at the 3rd day post-vaccination, plasmocyte and lymphatic cells become the predominant infiltrating cells in the ES at the 7th day. The KLH in the ES lumen were phagocytized at the 3-7th day post-vaccination. S-phase cells and IgG positive cells in ES increased markedly in the 3rd day and 7-14 days post-vaccination respectively with similar localization.
Conclusion: The activity of cell proliferation in the ES enhance and local proliferated cells may differentiate in situ into immunocompetent cells during the secondary immune response against TD antigen in the inner ear. This indicates that ES plays an important role in immune response of inner ear.