Expression Profile Analysis during Human Healthy Dental Pulp Development

Objectives: The aim of this research was to evaluate gene expression profile of human dental pulp in physiological conditions at three different development stages: Experiments were performed using microarray technique that allows to simultaneously analyze the expression levels of thousands of genes in a single experiment.

Methods: In the present study we report a microarray analysis carried out using high density array containing 21.329 transcripts in replicates comparing samples of human third molars pulp at three different stages: bud stage (age 13), during apex maturation (age 18) and of older subjects (age 57). Obtained data were statistically analyzed using the S.A.M system (Significance Analysis of Microarray) and I.P.A. (Ingenuity Pathways analysis). RT-PCR analysis was performed to validate significant microarray genes expression.

Results: Several genes, involved in development and cellular proliferation, were shortlisted from the compared analysis, and categorized in: genes involved in dentin and enamel mineralization, protoncogenes, collagen genes, metallopeptidases and growth factors. Expression of these genes decreased with progressive tissue maturation. I.P.A software identified networks and functional groups of genes involved in the different pulp development stages.

Conclusions: Expression profiles analysis during human dental pulp development can represent a sensible and useful tool for the study of mechanisms involved in differentiation, growth and evolution of human dental pulp in normal and pathological conditions.