Characterization of stratum intermedium in postnatal BALB/c mouse

Objective: To study the apoptosis of stratum intermedium cell and its distribution and expression of proliferating cell nuclear antigen(PCNA)、Tissue non-specific alkaline phosphatase(TNSALP) in postnatal stage of BALB/c mouse，so as to understand its role. Method: seventy two BALB/c mice in different day were killed and their bilateral mandibular first molar germs with surrounding alveolar bone were taken out，then the tissues were fixed with 4％ paraformaldehyde at 4℃ overnight，dehydrated，embedded in paraffin and serially sectioned at 5µm。Tdt-mediated Dutp nick end labeling (TUNEL) and Immunohistochemical assay were adopted to determine the tissue distribution and cellular localization of Bcl-2、PCNA and TNSALP。Result: TUNEL staining of apoptosis cells were observed in stratum intermedium and PCNA positive cells were expressed in the development of enamel.There were strong TNALP expressing in the stratum intermedium.

Conclusion:The stratum intermedium play an important regulating role during the differentiation of ameloblast and formation of ename