Microarray gene expression during early healing of GBR-treated calvarial critical size defects.
OBJECTIVE
To investigate the gene expression and molecular pathways implicated in the regulation of the osseous healing process following guided bone regeneration (GBR).


METHODS
Six 6-month-old Wistar male rats were used. Standardized 5-mm critical size defects were created in the parietal bones of each animal and treated with an extracranial and intracranial ePTFE membrane, according to the GBR principle. Three animals were randomly sacrificed after 7 and 15 days of healing. Total RNA was extracted from each sample and prepared for gene expression analysis. RNA quality and quantity were assessed, followed by hybridization of the cRNA to Affymetrix GeneChip Rat Genome 230 2.0 Arrays. The Affymetrix data were processed, and first-order analysis, quality control and statistical analysis were performed. Biological interpretation was performed via pathway and Gene Ontology (GO) analysis.


RESULTS
Between the 7- and 15-day samples, 538 genes were differently regulated. At day 7, inflammatory and immune responses were clearly upregulated. In addition, GO terms related to angiogenesis and cell cycle regulation were overexpressed. At day 15, a more complex cellular activity and cell metabolism were evident. The bone formation processes were significantly overexpressed, with several genes encoding growth factors, enzyme activity, and extracellular matrix formation found as upregulated. Remarkably, a negative regulation of Wnt signalling pathway was observed at 15 days.


CONCLUSIONS
The gene expression profile of the cells participating in osseous formation varied depending on the healing stage. A number of candidate genes that seem differentially expressed during early stages of intramembranous bone regeneration was suggested.
Department of Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
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Al-Kattan
Private Practice, London, UK.
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Retzepi
Department of Periodontology, UCL Eastman Dental Institute, London, UK.|Centre for Oral Clinical Research, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London (QMUL), London, UK.
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Calciolari
Centre for Oral Clinical Research, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London (QMUL), London, UK.
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Donos
D000818:Animals; D001861:Bone Regeneration / Q000235:genetics* / Q000502:physiology*; D015870:Gene Expression; D048091:Guided Tissue Regeneration; D008297:Male; D046228:Microarray Analysis; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D012886:Skull / Q000601:surgery*; D000072836:Surgical Wound; D014945:Wound Healing
critical size defect; gene expression; guided bone regeneration