Abstract:

Objective

To investigate the expression and distribution of Toll like receptor 4（TLR4） in human dental pulp tissue and odontoblasts and explore the role of TLR4 in the innate immune response.

Methods

Odontoblasts and pulp tissue were collected from extracted human teeth. Scanning electron microscopy （SEM） was performed on representative teeth to demonstrate the existence of an odontoblast monolayer. TLR4 mRNA levels of human pulp tissue and odontoblasts were assayed by reverse transcriptionpolymerse chain reaction （RT-PCR）.The expression and localization of TLR4 protein were studied with western blot and immunohistochemistry.

Results

SEM revealed the integrity of the odontoblast layer and the well-preserved morphology of the individual cells.RT-PCR demonstrated TLR4 mRNA expression in odontoblasts and healthy pulp tissue with a 278bp transcript. Western blot with TLR4-specific antibody also detected the 89 000 protein in these samples. Immunohistochemical staining detected TLR4 in odontoblasts in the dental pulp. Negative immunostaining was observed in the pulp fibroblasts. Some pulp capillary endothelial cell exhibited intense staining.

Conclusions

Human odontoblasts and pulp tissue express TLR4， which suggests that odontoblasts take part in the innate immune systerm and TLR4 may play an important role in the host defense of human dental pulp.

Key words: Dental pulp, Odontoblast, Toll like receptor4 （TLR4）