Impact of cigarette smoke on osteogenic and osteoclast signaling in middle palatal suture.

Considering that smoking is a public health problem that has been growing among adolescents, the aim of this study was to investigate the impact of cigarette smoke on osteogenic and osteoclastogenic signaling in middle palatal suture of rats. Male Wistar rats exposed (n = 30) or not to cigarette smoke (n = 30) were used. Exposure to smoke was carried out for two daily periods of 3 minutes each, with an interval of 12 hours between exposures. After the experimental periods of 3, 7, 14 and 21 days, the animals were euthanized. The collected tissues were analyzed using light microscopy and real-time RT-PCR was performed to investigate gene expression. The data obtained were compared using the Kruskal Wallis and Dunn tests (⍺ = 5%). Morphologically, there were no significant changes in the middle palatal suture of rats exposed or not to cigarette smoke during 3, 7, 14 and 21 days (p> 0.05). On the other hand, osteoclastogenic signaling was increased in animals exposed to smoke and was characterized by a higher production of RANKL at 3 and 14 days (p <0.05), with no change in the synthesis of RANK and osteoprotegerin (p> 0.05). Interestingly, in the exposed animals, an early increase in the synthesis of osteocalcin, bone sialoprotein and osteopontin was also identified at 3 days of exposure (p <0.05), not sustained over time (p> 0.05). Cigarette smoke modulates osteogenic and osteoclastogenic signaling in the middle palatal suture of young rats, although morphological changes have not been evidenced.

VEGF and FGF-2 Released In Palatal Suture after Rapid Maxillary Expansion (RME).

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) have the ability to increase vascular proliferation and permeability. The aim of this study was to quantify the release of two diffusible angiogenic growth factors (VEGF and FGF-2) after rapid maxillary expansion (RME). Thirty animals were randomly assigned to two groups. Control group (5 rats - intact suture) and Experimental groups (25 rats with RME) which were evaluated in different periods of treatment. Five animals were euthanized in different periods of healing at 0, 1, 2, 3, 5 and 7 days after RME. RT-PCR was used to evaluate the gene expression of angiogenic growth factors released on different periods of study. Data were submitted to statistical analysis using ANOVA followed by Tukey test and significance was assumed at a=0.05. RT-PCR showed that mRNAs of VEGF and FGF-2 were expressed in intact palatal suture tissue. mRNAs of VEGF and FGF-2 was upregulated in early periods (24 h) after RME (p<0.001 and p<0.01, respectively). The molecular levels of VEGF never returned to its original baseline values, and FGF-2 expression decreased up to day 5 (p<0.001) and suddenly increased at day 7, returning to its original level. RME increased VEGF secretion, but decreased FGF-2 secretion when compared to intact tissue. The results showed that these angiogenic growth factors are released and regulated in the palatal suture tissue after RME and could make an important contribution to the knowledge of overall reparative response of the suture tissue during the bone remodeling process.

The Effect of Cigarette Smoking And Low-Level Laser Irradiation in RANK/RANKL/OPG Expression.

The objective of this study was to investigate the effects of low-level laser therapy (LLLT) and cigarette smoke on alveolar socket osteoclastogenesis signaling after tooth extraction, in rats. Sixty male Wistar rats were randomly assigned to four groups with 15 animals each: Control Group (with right maxillary molar extraction - ME), Experimental I (with ME and LLLT), Experimental II (with ME and cigarette smoke) and Experimental III group (with ME, LLLT and cigarette smoke). Euthanasia was performed at 3, 7 and 14 days postoperative. qRT-PCR was used to evaluate expression of Tnfrsf11a (RANK), Tnfsf11 (Rankl) and Tnfrsf11b (OPG). Data were submitted to statistical analysis using two-way ANOVA followed by Bonferroni test (α=0.05). There was an upregulation of RANK, RANKL and OPG genes over all the time of healing in Exp I group compared to control group. Exp II group showed a decreased expression of all genes over time, whereas Exp III genes expression were higher than Exp II values but lower than Control and Exp I values over time. The results of this study concluded that the LLLT had a positive effect, whereas cigarette smoke had a negative effect on RANK, RANKL and OPG gene expression in bone remodeling process.

RANK/RANKL/OPG Expression in Rapid Maxillary Expansion.

The aim of this study was to evaluate osteoclastogenesis signaling in midpalatal suture after rapid maxillary expansion (RME) in rats. Thirty male Wistar rats were randomly assigned to two groups with 15 animals each: control (C) and RME group. RME was performed by inserting a 1.5-mm-thick circular metal ring between the maxillary incisors. The animals were euthanized at 3, 7 and 10 days after RME. qRT-PCR was used to evaluate expression of Tnfsf11 (RANKL), Tnfrsf11a (RANK) and Tnfrsf11b (OPG). Data were submitted to statistical analysis using two-way ANOVA followed by Tukey test (a=0.05). There was an upregulation of RANK and RANKL genes at 7 and 10 days and an upregulation of the OPG gene at 3 and 7 days of healing. Interestingly, an increased in expression of all genes was observed over time in both RME and C groups. The RANKL/OPG ratio showed an increased signaling favoring bone resorption on RME compared to C at 3 and 7 days. Signaling against bone resorption was observed, as well as an upregulation of OPG gene expression in RME group, compared to C group at 10 days. The results of this study concluded that the RANK, RANK-L and OPG system participates in bone remodeling after RME.

Impact of cigarette smoke on osteogenic and osteoclast signaling in middle palatal suture

Abstract Considering that smoking is a public health problem that has been growing among adolescents, the aim of this study was to investigate the impact of cigarette smoke on osteogenic and osteoclastogenic signaling in middle palatal suture of rats. Male Wistar rats exposed (n = 30) or not to cigarette smoke (n = 30) were used. Exposure to smoke was carried out for two daily periods of 3 minutes each, with an interval of 12 hours between exposures. After the experimental periods of 3, 7, 14 and 21 days, the animals were euthanized. The collected tissues were analyzed using light microscopy and real-time RT-PCR was performed to investigate gene expression. The data obtained were compared using the Kruskal Wallis and Dunn tests (⍺ = 5%). Morphologically, there were no significant changes in the middle palatal suture of rats exposed or not to cigarette smoke during 3, 7, 14 and 21 days (p> 0.05). On the other hand, osteoclastogenic signaling was increased in animals exposed to smoke and was characterized by a higher production of RANKL at 3 and 14 days (p <0.05), with no change in the synthesis of RANK and osteoprotegerin (p> 0.05). Interestingly, in the exposed animals, an early increase in the synthesis of osteocalcin, bone sialoprotein and osteopontin was also identified at 3 days of exposure (p <0.05), not sustained over time (p> 0.05). Cigarette smoke modulates osteogenic and osteoclastogenic signaling in the middle palatal suture of young rats, although morphological changes have not been evidenced.

Resumo Considerando que a fumaça de cigarro é um problema de saúde pública que está crescendo entre os adolescentes, o objetivo deste estudo foi investigar o impacto da fumaça de cigarro na sinalização osteogênica e osteoclastogênica da sutura palatina mediana de ratos. Foram utilizados ratos Wistar machos expostos (n=30) e não expostos à fumaça de cigarro (n=30). A exposição à fumaça de cigarro foi realizada duas vezes ao dia por 3 minutos, com um intervalo de 12 horas entre as exposições. Os animais foram mortos após o período experimental de 3, 7, 14 e 21 dias. Os tecidos coletados foram analisados em microscópico de luz e pelo RT-PCR em tempo real foi realizado para investigar a expressão gênica. s dados obtidos foram comparados usando o testes de Kruskal Wallis e Dunn (⍺ = 5%). Morfoligicamente, não houve mudança significativa na sutura palatina mediana nos ratos expostos ou não à fumaça de cigarro durante os tempo de 3, 7, 14 e 21 dias (p> 0.05). Por outro lado, a sinalização osteogênica esta aumentada nos animais expostos à fumaça e foi caracterizado por um aumento da produção de RANKL aos 3 e 14 dias (p <0.05), sem mudança na síntese da produção de RANK e osteoprotegerina (p> 0.05). Curiosamente, nos animais expostos, também foi observado um aumento precoce da síntese de osteocalcina, sialoproteína óssea e de osteopontina aos 3 dias de exposição, o que não foi mantido ao longo do tempo. A fumaça de cigarro modula a sinalização osteogênica e osteoclastogênica na sutura palatina mediana de ratos jovens, apesar de não tenha sido evidenciado alterações morfológicas.

RANK/RANKL/OPG Expression in Rapid Maxillary Expansion

Abstract The aim of this study was to evaluate osteoclastogenesis signaling in midpalatal suture after rapid maxillary expansion (RME) in rats. Thirty male Wistar rats were randomly assigned to two groups with 15 animals each: control (C) and RME group. RME was performed by inserting a 1.5-mm-thick circular metal ring between the maxillary incisors. The animals were euthanized at 3, 7 and 10 days after RME. qRT-PCR was used to evaluate expression of Tnfsf11 (RANKL), Tnfrsf11a (RANK) and Tnfrsf11b (OPG). Data were submitted to statistical analysis using two-way ANOVA followed by Tukey test (a=0.05). There was an upregulation of RANK and RANKL genes at 7 and 10 days and an upregulation of the OPG gene at 3 and 7 days of healing. Interestingly, an increased in expression of all genes was observed over time in both RME and C groups. The RANKL/OPG ratio showed an increased signaling favoring bone resorption on RME compared to C at 3 and 7 days. Signaling against bone resorption was observed, as well as an upregulation of OPG gene expression in RME group, compared to C group at 10 days. The results of this study concluded that the RANK, RANK-L and OPG system participates in bone remodeling after RME.

Resumo O objetivo deste estudo foi avaliar a sinalização osteoclastogenese na sutura palatina após a expansão rápida da maxila (ERM) em ratos. Um total de 30 ratos Wistar machos foram divididos aleatoriamente em dois grupos com 15 animais cada: controle (C) e grupo ERM. ERM foi realizada através da inserção de um anel de metal circular de 1,5 mm de espessura entre os incisivos superiores. Os animais foram sacrificados aos 3, 7 e 10 dias após a RME. qRT-PCR foi utilizado para avaliar a expressão de Tnfsf11 (RANKL), Tnfrsf11a (RANK) e TNFRSF11b (OPG). Os dados foram submetidos à análise de variância de duas vias, seguido pelo teste de Tukey (a=0,05). Houve uma regulação positiva de genes RANK e RANKL aos 7 e 10 dias e uma regulação positiva do gene OPG aos 3 e 7 dias de tratamento. Curiosamente, foi observado um aumento na expressão de todos os genes ao longo do tempo nos grupos ERM e C. O RANKL/OPG mostrou um aumento na sinalização favorecendo a reabsorção óssea no ERM em comparação com o C nos períodos de 3 e 7 dias. Foi observada uma sinalização contra a reabsorção óssea, assim como, uma regulação favorável da expressão do gene OPG no grupo ERM, comparado ao grupo C aos 10 dias. Os resultados deste estudo permitem concluir que o sistema RANK, RANK-L e OPG participa de remodelação óssea após a ERM.