OBJECTIVETo study the gene expression profiles of traumatic occlusion in early stage with the animal model of rats.

METHODSThe occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissue of the first molars at the both sides of rats' lower jaws were taken out under anesthesia. The different expressive genes were shown by genome-wide microarray, which comprises about 27 000 genes and analyzed the different expressive genes with Pathway and GO analysis, finally the results of the microarray were examined by real time-polymerase chain reaction (RT-PCR).

RESULTSIn the results of the study, 586 different expressions were found, of which the expressions of 166 genes increased and 420 genes decreased. 106 different pathways were involved with Pathway analysis and 270 different functional classification related to GO analysis.

CONCLUSIONThe balance of the lower alveolar bone is destroyed after 24 hours of traumatic occlusion. At early phase of the occlusal trauma, osteogenesis and bone formation in alveolar bone are inhibited, yet osteoblast genesis and bone resorption are not significant.

Alveolar Bone Loss ; Animals ; Bone Resorption ; Dental Occlusion ; Dental Occlusion, Traumatic ; Mandible ; Molar ; Osteoblasts ; Osteogenesis ; Rats ; Transcriptome

OBJECTIVETo study the intercellular communication of alveolar bone during traumatic occlusion at early stage in rats.

METHODSThe occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissues of the lower jaws first molars at the both sides were taken out under anesthesia The various 27 000 genes were identified with genome-wide microarray, and further were investigated with reverse transcription-polymerase chain reaction (RT-PCR) and Pathway analysis.

RESULTSTotal 586 gene were found to be changed, 106 different signal pathways got involved with Pathway analysis, including cell adhesion molecules(CAMS), adhesions junction, gap junction, focal adhesion and tight junction, and the cytokines associated with bone metabolism in above 5 signal pathways were all down-regulated.

CONCLUSIONAt the early phase of the occlusal trauma, intercellular communication in rat's alveolar bone were inhibited.

Alveolar Process ; Animals ; Bone and Bones ; Dental Occlusion ; Dental Occlusion, Traumatic ; Molar ; Rats

OBJECTIVETo explore the suitable level and action time of 17-beta estradiol and fluid shear stress (FSS) and their combined effect on the proliferation of rat osteoblasts in vitro.

METHODSMC3T3-E1 osteoblasts were adopted after subcultured and different concentrations of 17-beta estradiol and FSS values were applied respectively on MC3T3-E1, the suitable level of 17-beta estradiol and FSS were selected through MTT and alkaline phosphatase (ALP). Then the two factors at the suitable level were applied simultaneously to MC3T3-E1 to detect the proliferation activity.

RESULTSSeventeen-beta estradiol(10(-8) mol x L(-1) for 5 d and 12 x 10(-5) N FSS for 60 min exhibited better effects on the proliferation activity than the other groups respectively, and the combined effect of both factors was better than any single-factor treated group.

CONCLUSIONBoth 17-beta estradiol and FSS have a suitable threshold in promoting proliferation of osteoblasts, and two-factor treated group exhibits better effect than any other single-factor treated groups. Therefore 17-beta estradiol and FSS have a synergetic action on differentiation and proliferation of osteoblasts.

Alkaline Phosphatase ; Animals ; Cell Differentiation ; Estradiol ; Osteoblasts ; Rats ; Stress, Mechanical