Methods: Dental pulp fibroblasts were established from cells growing out of the dental pulp tissue of deciduous and permanent non-carious teeth. For microarray assays, total RNA was isolated from each sample using the Trizol reagent. To confirm the microarray results, insulin-like growth factor-binding protein 5 (IGFBP5) and vascular endothelial growth factor A (VEGFA) showing higher mRNA expression levels were selected and analyzed for their mRNA levels by RT-PCR.
Results: A scatter plot of mRNA levels based on fluorescent signals in human dental pulps from deciduous and permanent teeth indicated a dispersed distribution pattern. In a scatter plot of the genes, 2573 genes were expressed at 2-fold higher levels in dental pulp from deciduous teeth, compared with permanent teeth. The RT-PCR results indicated that both the IGFBP5 and VEGFA mRNA levels were upregulated by about 3-fold in dental pulp from deciduous teeth compared with permanent teeth. Thus, the RT-PCR results for these genes were consistent with the microarray data.
Conclusion: The dental pulps in deciduous and permanent teeth differ significantly with regard to their developmental processes, tissue structures and functions. Thus, the present findings using DNA microarray analyses to detect differences in the gene expressions of deciduous and permanent teeth may be useful for dental pulp tissue engineering.