IADR Abstract Archives
The Timing of the Parotid Gland Opening Into the Oral Cavity
Objectives: There are three pairs of major salivary glands: the parotid glands (PG), the submandibular glands (SMG), and the sublingual glands (SLG). The SMG and SLG have already opened into the oral cavity by the time of birth, whereas the PG remains closed and does not secrete saliva into the oral cavity at this point of development. However, it has been unclear when and how the PG opens into the oral cavity after birth. The present study was performed to investigate this issue, and the genes involved in parotid duct opening.
Methods: We employed C57BL6J mice at embryonic day (E) 18 and at postnatal days (P) 2, 3, 4, and 6, respectively. A total of 31 C57BL6J mice were used in this study. All experiments involving mice were approved by the IACUC Committee at Tokyo Dental College. Before demineralization with 10% ethylenediaminetetraacetic acid, all the mice were fixed in 4% phosphate-buffered paraformaldehyde. Paraffin blocks were then prepared using standard methods, and a series of tissue sections 5-10μm thick were cut using a sliding microtome. We then prepared frontal sections, followed by staining with hematoxylin and eosin (H&E) and immunohistochemical staining for SOX9.
Results: We found that the parotid duct did not open before birth, but opened into the oral cavity on P4. Expression of SOX9 was significantly decreased just before parotid duct opening.
Conclusions: Our results suggest that SOX9 may be involved in opening of the parotid duct.
Methods: We employed C57BL6J mice at embryonic day (E) 18 and at postnatal days (P) 2, 3, 4, and 6, respectively. A total of 31 C57BL6J mice were used in this study. All experiments involving mice were approved by the IACUC Committee at Tokyo Dental College. Before demineralization with 10% ethylenediaminetetraacetic acid, all the mice were fixed in 4% phosphate-buffered paraformaldehyde. Paraffin blocks were then prepared using standard methods, and a series of tissue sections 5-10μm thick were cut using a sliding microtome. We then prepared frontal sections, followed by staining with hematoxylin and eosin (H&E) and immunohistochemical staining for SOX9.
Results: We found that the parotid duct did not open before birth, but opened into the oral cavity on P4. Expression of SOX9 was significantly decreased just before parotid duct opening.
Conclusions: Our results suggest that SOX9 may be involved in opening of the parotid duct.