ABSTRACT
ObjectiveIsoproterenol (ISO) stimulates the β2-adrenoceptor to enhance osteoclast formation, thus accelerating bone resorption. This study was to explore the effect of β-adrenoceptor agonist ISO on orthodontic tooth movement in rats.MethodsForty healthy 8-week-old SD male rats with the upper right first molar moved proximally by 50 g force application were randomly divided into an ISO and a control group and injected intraperitoneally with ISO at 5 mg/kg/d and the same amount of saline, respectively. Five rats were sacrificed in each group after 0, 7, 14 and 21 days of orthodontic force application and the upper right maxillary harvested for measuring the distance of movement of the upper right first molar, observing the changes in the periodontal tissue by HE staining, and counting the osteoclasts by tartrate-resistant acid phosphatase staining (TRAP).ResultsAt 7, 14 and 21 days of orthodontic force application, the tooth movement distance was significantly larger in the ISO group (\[0.52±0.04\], \[0.84±0.05\] and \[1.11±0.15\] mm) than in the control (\[0.40±0.07\], \[0.62±0.06\] and \[0.85±0.07\] mm) (P<0.05). On HE staining, the alveolar bone resorption at the pressure side was the most significant at 14 days, and obvious new bone formation was observed in the alveolar bone at 21 days. At 7, 14 and 21 days, TRAP staining showed remarkably larger numbers of osteoclasts in the ISO group (13.8±3.3, 24±6.3 and 18.8±2.6) than in the control (9.6±1.9, 14.6±3.7, 10.4±3.1) (P<0.05).ConclusionIsoproterenol can increase the number of osteoclasts and accelerate the movement of the orthodontic tooth in rats.
ABSTRACT
Objective SCAP are seen as seed cells of peri-apical tissue regeneration and used in periapical tissue regeneration project based on stem cells .In this study, we aim to explore the ef-fectdifferent mechanical stretch stress on the proliferation and differen-tiation potential of human stem cells from the apical papilla ( SCAP ) ,and to clarify the mechanism of how mechanical stretch stress regulate human SCAP ,which will provide theoretical guidance for ortho-dontic treatment . Methods Human SCAP was isolated , cultured and identified by combined explants method and enzymatic separa-tion method and limited dilution .MTT assay was used to detect the effect different static mechanical stretch stress stimulation have on the proliferation of SCAP .Western blot was used to detect the expression changes of SCAP osteogenesis /odontoblast differentiation-re-lated protein (ALP, OSX,DSP) under mechanical stretch stressand to detect the expression of SCAP endoplasmic reticulum stress mo -lecular chaperone GRP 78 under different static mechanical stretch stress . Results SCAP were successfully isolated and cultured , and we induced SCAP to differentiate into osteoblasts and adipocytes successfully by osteogenic medium and adipogenic medium .Flow cytometry was performed in accordance with SCAP immunophenotype .Compared with the control group , 150g mechanical stretch stress stimulation promoted SCAP proliferation first and then inhibited SCAP proliferation [(0.481±0.226),(1.375±0.104),(1.425± 0.136),(1.556±0.268),(0.589±0.29),P<0.05].It was same in the 200g group.250g mechanical stretch stress stimulation signifi-cantly inhibited SCAP proliferation [(0.373±0.146),(0.545±0.069),(0.745±0.273),(0.967±0.278),(1.060±0.362),P<0.05]. The expression levels of ALP , OSX and DSP protein in each group were higher than those in the control group (P<0.05).Compared with the control group, the expression of GRP78 protein was up-regulated (P<0.05). Conclusion Mechanical stretch stress could regulate the SCAP proliferation and osteogenesis/odontoblast differentiation .What′s more,endoplasmic reticulum stress played a role in osteogenesis/odontoblast differentiation under mechanical stretch stress and promoted SCAP osteogenesis /odontoblast differentiation .
ABSTRACT
Objective SCAP are seen as seed cells of peri-apical tissue regeneration and used in periapical tissue regeneration project based on stem cells .In this study, we aim to explore the ef-fectdifferent mechanical stretch stress on the proliferation and differen-tiation potential of human stem cells from the apical papilla ( SCAP ) ,and to clarify the mechanism of how mechanical stretch stress regulate human SCAP ,which will provide theoretical guidance for ortho-dontic treatment . Methods Human SCAP was isolated , cultured and identified by combined explants method and enzymatic separa-tion method and limited dilution .MTT assay was used to detect the effect different static mechanical stretch stress stimulation have on the proliferation of SCAP .Western blot was used to detect the expression changes of SCAP osteogenesis /odontoblast differentiation-re-lated protein (ALP, OSX,DSP) under mechanical stretch stressand to detect the expression of SCAP endoplasmic reticulum stress mo -lecular chaperone GRP 78 under different static mechanical stretch stress . Results SCAP were successfully isolated and cultured , and we induced SCAP to differentiate into osteoblasts and adipocytes successfully by osteogenic medium and adipogenic medium .Flow cytometry was performed in accordance with SCAP immunophenotype .Compared with the control group , 150g mechanical stretch stress stimulation promoted SCAP proliferation first and then inhibited SCAP proliferation [(0.481±0.226),(1.375±0.104),(1.425± 0.136),(1.556±0.268),(0.589±0.29),P<0.05].It was same in the 200g group.250g mechanical stretch stress stimulation signifi-cantly inhibited SCAP proliferation [(0.373±0.146),(0.545±0.069),(0.745±0.273),(0.967±0.278),(1.060±0.362),P<0.05]. The expression levels of ALP , OSX and DSP protein in each group were higher than those in the control group (P<0.05).Compared with the control group, the expression of GRP78 protein was up-regulated (P<0.05). Conclusion Mechanical stretch stress could regulate the SCAP proliferation and osteogenesis/odontoblast differentiation .What′s more,endoplasmic reticulum stress played a role in osteogenesis/odontoblast differentiation under mechanical stretch stress and promoted SCAP osteogenesis /odontoblast differentiation .