Expression of Cbfa1, ALP, extracellualr matrix in dental follicle cells

Objectives: To study the expression of extracellular matrix in mouse dental follicle cells of different develpmental stages and explore their expression sequence as well as the cytodifferentiation of dental follicle cells during periodontium development. Methods: Dental follicle cells from 3,5,7 and 9 day-old Balb/c mice were cultured in vitro. Immunocytochemistry was used to detect the expression of cbfa1, ALP, BSP, OPN and OC. Furthermore, RT-PCR was used to detect the mRNA expression of cbfa1 and ALP. Results: The expression pattern of ALP was as follows: The dental follicle cells from 3 day-old mouse were all ALP –negative , positive expression appeared in the cells from 5-day-old mouse, and the majortity were positive cells on day 9. According to the expression of bone-related proteins, dental follicle cells could be divided into two subtypes: negative and positive. The only difference among the three proteins was that the timing of positive cells presence and the quantity of positive cells. As far as BSP and OC were concerned, all dental follicle cells were negative from 3 and 5 day-old mouse, positive cells appeared on day 7 and day 9, but the majority were still negative. When it comes to OPN, positive cells appeared on day 3, but the amount of positive cells reduced on day 7, and all cells were negative on day 9. No expression of cbfa1 was detected by immunocytochemistry, however, cbfa1 mRNA was detected in dental follilce cells of 3 day-old mouse by RT-PCR. Moreover, the expression of cbfa1mRNA kept on presenting in dental follilce cells of 5,7,9-day-old mouse. Conclusions: The expression pattern of ALP, BSP, OPN and OC in mouse dental follicle cells indicates that dental follicle comprises at least two phenotypes: osteoblasts(cementoblasts) and fibroblasts. Moreover, different phenotypes exhibit during different stages of periodontium development. (No.30371537).