Bone Remodeling In Rats Research Articles

PPIA, HRPT1, and PGK1 genes as the appropriate combination for RT-qPCR normalization in alveolar and femoral bone remodeling in olanzapine-treated rats.

Reliable gene expression analysis in bone remodeling studies requires an appropriate selection of internal controls, i.e. stable reference genes for the normalization of quantitative real-time PCR (RT-qPCR), the most common method used for quantifying gene expression measurements. Even the most widely used reference genes can have variable expression under different experimental conditions, or in different tissue types or treatment regimes, so selecting appropriate controls is a key step in ensuring reliable results. The aim of this research was to identify the most stable reference gene(s) for the study of olanzapine modulated bone remodeling in rats. RNA was isolated from the maxillary alveolar and femoral bones of olanzapine or placebo-treated Wistar rats and transcribed to cDNA. The expression of 12 candidate reference genes was assessed by RT-qPCR. Their expressions were analysed using GeNorm, NormFinder, BestKeeper and delta Ct algorithms, and by the comprehensive ranking method. PPIA, HRPT1 and PGK1 were the most stably expres sed reference genes and the combination of the three genes was optimal for normalization. This study is the first to identify the optimal reference genes for research in olanzapine-exposed rats, which serve as a pivotal benchmark for enhancing the accuracy and reliability of future RT-qPCR expression in bone studies.

Effects of coenzyme Q10 on orthodontic tooth movement and alveolar bone remodeling in rats.

To evaluate the effects of coenzyme Q10 (CoQ10) on alveolar bone remodeling and orthodontic tooth movement (OTM). An orthodontic appliance was placed in 42 female Sprague‒Dawley rats were divided into two groups: the orthodontic force (OF) group (n = 21) and the OF + CoQ10 (CoQ10) treatment group (n = 21). Each group was divided into 3 subgroups, and the rats were sacrificed on days 3, 7 and 14. The rats in CoQ10 and OF groups were administered 100mg/kg b.w./day CoQ10 (in 1 mL/b.w. soybean oil) and 1 mL b.w./day soybean oil, respectively, by orogastric gavage. The OTM was measured at the end of the experiment. The osteoclast, osteoblast and capillary numbers; vascular endothelial growth factor (VEGF), receptor activator nuclear kappa B ligand (RANKL) and osteoprotegrin (OPG) levels in tissue; and total antioxidant status (TAS) and total oxidant status (TOS) in blood were determined. Compared with the OF group, the CoQ10 treatment group exhibited decreased orthodontic tooth movement and osteoclast and capillary numbers. Indeed, the levels of VEGF and RANKL decreased, while the levels of OPG increased except on day 7. Additionally, the CoQ10 treatment group exhibited lower TOS and higher TAS on days 7 and 14 (p < 0.05). Histological findings showed that the morphology of osteoblasts changed in the CoQ10 group; however, there was no significant difference in the number of osteoblasts between the groups (p > 0.05). Due to its effect on oxidative stress and inflammation, CoQ10 regulates bone remodeling by inhibiting osteoclast differentiation, promoting osteoblast differentiation and reducing the amount of OTM. Considering that OTM may be slowed with the use of CoQ10, topics such as orthodontic treatment duration, orthodontic force activation and appointment frequency should be considered in treatment planning. It is predicted that the use of CoQ10 will support the effectiveness of treatment in clinical applications such as preventing relapse in orthodontic treatment by regulating bone modulation and anchorage methods that suppress/optimize unwanted tooth movement.

CYTOKINES AND PROTEINS OF THE EXTRACELLULAR MATRIX IN THE BLOOD OF RATS OF DIFFERENT AGES AFTER FILLING THE DEFECT IN THE FEMORAL METAPHYSIS WITH ALLOGENEIC BONE IMPLANTS SATURATED WITH MESENCHYMAL STEM CELLS

Mesenchymal stem cells (MSCs) are used for the improvement of the repair of allografts.&#x0D; Aim. Based on the analysis of cytokines and proteins of the extracellular matrix in the blood serum of laboratory rats, to evaluate the course of metabolic processes after filling a defect in the femoral metaphysis with allogeneic bone implants saturated with MSCs.&#x0D; Material and Methods. On the model of a transcortical defect in the metaphysis of the femur, the content in the blood serum of 3 and 12 months white rats of interleukin-1 (IL-1), interleukin-6 (IL-6), transforming growth factor-b (TGF-b), osteocalcin (OC) and osteopontin (OP) on the 14th, 28th and 90 days was investigated.&#x0D; Results and Discussion. Use of MSCs in 3-month-old rats led to an increase in IL-1 concentration: 0.300(0.269; 0.329, 0.308(0.273; 0.339), 0.295(0.271; 0.319) pg/ml of IL-1 for the 14th, 28th and 90th days, respectively, which higher than the level of rats without MSCs by 1.69 (p=0.008), 1.37 (p=0.008) and 1.46 (p=0.008) times, respectively. For 12-month-old rats: IL-1 (0.414(0.387;0.437), 0.426(0.389; 0.448) and 0.407(0.368;0.423) pg/ml on the 14th, 28th and 90th days, respectively), which exceeded the data of rats without MSCs in 1.69 (p=0.008); 1.38 (p=0.008) and 1.46 times (p=0.008). In the blood serum of rats with MSCs TGF-b: 3-month: - 1.826(1.637;2.015), 1.379(1.247; 1.568) and 1.675(1.476;1.893) ng/ml on the 14th, 28th and 90th days, respectively, which was 1.57 (p=0.008), 1.98 (p=0.008) and 1.51 (p=0.008) times less than the data of the comparison group; 12-month-old - 1.976(1.749; 2.234), 1.492(1.218;1.734) and 1.813(1.636;2.028) ng/ml on the 14th, 28th and 90th days, respectively, which is less than the level of rats without MSCs of 1.50 ( p=0.008), 1.92 (p=0.008) and 1.51 (p=0.008) times. When introducing MSCs OP: 3-month-old rats - 13.55(12.90; 14.04), 14.14(13.43;14.87) and 14.12(13.75;14.77) ng/ml, which was higher than in rats without MSCs in 1.11 (p=0.008), 1.11 (p=0.008) and 1.17 (p=0.008) times; 12-month-old - 15.26(14.70; 15.81), 16.38(15.88; 16.91) and 16.06(15.53; 16.67) ng/ml, which is more than the comparison group 1.11 (p=0.008), 1.16 (p=0.008) and 1.22 (p=0.008) times;&#x0D; Conclusions. Saturation of allografts with MSCs led to an increase in biochemical markers of inflammation from the 14th day. Bone remodeling in rats with MSCs was characterized by lower activity. In 12-month-old rats in comparison with 3-month-old animals we noted more active inflammation, with a slowed activity in bone remodeling.

Influence of ibuprofen combined with corticotomy on tooth movement and alveolar bone remodeling in rats.

To investigate the effects of corticotomy-assisted orthodontic tooth movement and administration of ibuprofen on tooth movement rate and alveolar bone response. A total of 78 adult male Wistar rats were randomly assigned to five groups: one baseline group (no treatment) and four experimental groups including orthodontic tooth movement only (OTM), orthodontic tooth movement with ibuprofen (OTMI), corticotomy-assisted orthodontic tooth movement (COTM), and corticotomy-assisted orthodontic tooth movement with ibuprofen (COTMI). Corticotomy was performed on a maxillary molar unilaterally. Nickel-titanium closed-coil springs generated a 10-gram force for maxillary first molar movement. The experimental drug groups received 15 mg/kg of ibuprofen, and the other groups received reverse osmosis water. Tooth movement and bone volume fraction were evaluated by micro-computed tomography on days 0, 7, 14, and 21. The corticotomy groups had statistically significantly higher tooth movement and lower bone volume fraction than the orthodontic groups (P &lt; .05). The amount and rate of tooth movement were statistically significantly different between the OTM and OTMI groups, but not statistically significantly different in bone volume fraction. However, statistically significant differences were not observed in any measurements between the COTM and COTMI groups. Ibuprofen during orthodontic tooth movement inhibited tooth movement and alveolar bone remodeling but had no effect on corticotomy-assisted orthodontic treatment.

Monitoring orthodontic tooth movement in rats after piezocision by bone scintigraphy.

Piezocision, corticocision of mineralized tissue by ultrasound showed promising results in accelerating tooth movement induced by orthodontic appliances although the biologic effects of this procedure are not well-understood so far. The aim of this study was to investigate the impact of piezocision on bone remodeling in rats by bone SPECT imaging. Ten male Wistar rats underwent surgical placement of orthodontic appliances on each side of the maxilla followed by piezocision on one side only. Each rat underwent 99mTc-MDP bone SPECT/CT imaging before surgery (T0), and 2 (T1) and 4 weeks (T2) after surgery. Bone uptake is expressed as median [IQR] min-max in percentage of the injected activity per ml computed from the 10 voxels with the highest uptake (%IAmax10/ml). Pooled data regardless of the piezocision showed a significant increase in bone uptake from T0 (3.2 [2.8-3.9] 2.6-4.9) to T1 (4.4 [3.8-4.6] 3.4-4.8; p = 0.001). Thereafter, the uptake decreased to T2 (3.8 [3.1-4.4] 2.8-4.8; p = 0.116). No significant differences in bone uptake were found between the maxilla sides without and with piezocision: T1: without (4.3 [3.8-4.5] 3.4-4.8) vs. with (4.5 [3.7-4.6] 3.5-4.7; p=0.285), T2: without (4.0 [3.1-4.5] 2.8-4.8) vs. with (3.7 [3.0-4.4] 2.8-4.8; p=0.062). 99mTc-MDP bone SPECT imaging in rats was able to reproduce changes in bone uptake in the maxilla after placement of orthodontic appliances inducing measurable tooth movement. An additional effect of piezocision on bone remodeling in terms of bone uptake was not detectable which is probably due to the pronounced and significant effects induced by the orthodontic appliances per se, which may mask the potential effects of additional piezocision.

Evaluation of the effect of Simvastatin Therapy on Bone remodeling in Rats

Objective: The aim of this study was to evaluate the effect of simvastatin on the bone remolding markers in rats (experimental study). Materials and methods: The study involved 18 male Wistar rats, they were divided into three groups: Group I (n=6; control group), Group II (n=6; was administrated 7.5 mg/kg/ dexamethasone intra muscular for 2 months served as a model of osteoporosis [op]), Group III (n=6;was administered 7.5 mg/kg/ dexamethasone intra muscular for 2month and treated orally with 8mg/kg of simvastatin).After 8 weeks, serum acid phosphatase was determined for the three group. Results: The levels of serum acid phosphatase were notably elevated in the [op] group. Administration of simvastatin produced a significant decrease in the levels of serum acid phosphatase. Conclusion: simvastatin was able to decrease the rate of bone resorption in an animal model of osteoporosis induced by dexamethasone.

Retracted: Dynamic Evaluation of Orthodontically-Induced Tooth Movement, Root Resorption, and Alveolar Bone Remodeling in Rats by in Vivo Micro-Computed Tomography.

This publication has been retracted by the Editor due to the identification of non-original figure images and manuscript content that raise concerns regarding the credibility and originality of the study and the manuscript. Reference: Jianping Zhou, Fengxue Yang, Xiaolin Xu, Gang Feng, Jun Chen, Jinglin Song, Hongwei Dai. Dynamic Evaluation of Orthodontically-Induced Tooth Movement, Root Resorption, and Alveolar Bone Remodeling in Rats by in Vivo Micro-Computed Tomography. Med Sci Monit, 2018; 24: 8306-8314. DOI: 10.12659/MSM.912470.

Dronabinol inhibits alveolar bone remodeling in tooth movement of rats

Orthodontic tooth movement is reliant on the process of bone remodeling, and a variety of medications impact the ability of teeth to move through bone. Marijuana is the most widely used recreational drug in the world, and early studies suggest the drug impacts bone remodeling as tetrahydrocannabinol binds to cannabinoid receptors which play a role in bone homeostasis. This study aimed to assess the impact of dronabinol on alveolar bone remodeling in rats with otherwise healthy tissue when subjected to orthodontic forces.Thirty male Sprague Dawley rats were equally allocated into 2 groups. Orthodontic appliances were placed in all animals, which consisted of a nickel-titanium coil ligated from the maxillary first molar to the central incisor. The appliance was activated to deliver a force to move teeth together. Over 21 days, daily injections of either dronabinol or the control (solvent) were given to the rats. Cephalometric analysis, histology, and bone remodeling profiles of both groups were analyzed and compared.Teeth moved in both the dronabinol and control groups (P <0.05). Tooth movement in the control group followed the typical process of orthodontic tooth movement: periodontal width narrowing and bone resorption on the compression side of the tooth, with an overall decrease in the height of the alveolar bone. In contrast, the dronabinol group showed an abnormal response to tooth movement: no bone resorption on the compression side of the tooth, increased bone formation on the tension side, and the maintenance of the height of the alveolar crest. In the dronabinol group, there were also significantly more osteoclasts and osteoblasts in the alveolar bone than in the control group.These results demonstrate that dronabinol attenuates orthodontic tooth movement by decreasing bone resorption, which could have implications for other bone-related recovery processes.

Effect of nicotine on orthodontic tooth movement and bone remodeling in rats.

ObjectiveTo quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining.MethodsThirty-nine adult male Sprague–Dawley rats were randomized into three groups group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal–Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM.ResultsAll six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days.ConclusionsThe findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

Voluntary exercise blocks ongoing pain and diminishes bone remodeling while sparing protective mechanical pain in a rat model of advanced osteoarthritis pain.

Exercise is the most common treatment recommended by healthcare providers for the treatment of musculoskeletal pain. We examined whether voluntary running wheel exercise improves pain and bone remodeling in rats with monosodium iodoacetate-induced unilateral knee joint pain. During acquisition of wheel running before osteoarthritis (OA) treatment, rats separated into 2 groups characterized by either high or low levels of voluntary wheel running as indicated by distance and peak speed. After the induction of knee joint OA, all rats showed diminished voluntary wheel running throughout the study. Voluntary wheel running failed to alter evoked nociceptive responses evaluated as weight asymmetry or hind paw tactile thresholds at any timepoint of the study. By contrast, relief of ongoing pain was demonstrated by conditioned place preference produced by lidocaine injection into the monosodium iodoacetate-treated knee in high but not low-running rats. Both high and low voluntary runners showed diminished trabecular bone loss compared with sedentary controls. These observations indicate that both high-intensity and low-intensity exercise is beneficial in protecting against bone remodeling in advanced OA. The data suggest that similar to clinical observation, bone remodeling does not correlate with pain. In addition, these results suggest that higher intensity exercise may relieve persistent ongoing OA pain while maintaining movement-evoked nociception. The relief of ongoing pain can potentially offer significant improvement in quality of life, whereas preservation of responses to movement-evoked pain may be especially important in protecting the joint from damage because of overuse.

Effects of efavirenz and tenofovir on bone tissue in Wistar rats.

Clinical trials indicate an increased risk of osteoporosis and bone fractures in people infected with human immunodeficiency virus (HIV). The pathogenesis of bone disturbances in HIV-positive patients is unknown, but it is suggested that antiretroviral drugs may be involved. To assess the effects of efavirenz (EF) and tenofovir (T) on bone remodeling in rats. The study involved 36 male Wistar rats divided into 3 groups, receiving normal saline (control group - group C), efavirenz (group EF) or tenofovir disoproxil (group T). After 24 weeks of the study, the following observations were made: In blood serum of the EF group compared to group C, there were increased levels of tartrate-resistant acid phosphatase form 5b (TRAP) and inorganic phosphorus. In the densitometric examination, group T showed a lower total body (TB) bone mineral density (BMD) than group C. In the immunohistochemical assessment, group EF showed a higher intensity and extension of anti-tartrate resistant acid phosphatase antibodies (abTRAP) compared to group C. In the histopathological examination of the second lumbar vertebra (L2), group EF showed a lower bone surface/volume ratio (BS/BV) and higher trabecular thickness (Tb.Th) than the control group. In the histopathological examination of the femur, a lower bone surface/tissue volume (BS/TV) and lower trabecular number (Tb.N) were found in group T compared to in group C. A lower value of the Young's modulus was observed in the four-point bending trial in groups EF and T compared to group C. The results of this study indicate that EF affects bone microarchitecture and leads to impaired biomechanical properties of bones in rats. Additionally, the negative effect of T on bone tissue was confirmed.

Rosamultin Attenuates Acute Hypobaric Hypoxia-Induced Bone Injuries by Regulation of Sclerostin and Its Downstream Signals.

Wang, Xing-Min, Hui Liu, Jian-Yu Li, Jin-Xia Wei, Xia Li, Yong-Liang Zhang, Ling-Zhi Li, and Xi-Zheng Zhang. Rosamultin attenuates acute hypobaric hypoxia-induced bone injuries by regulation of sclerostin and its downstream signals. High Alt Med Biol. 21:273-286, 2020. Background: Rosamultin, one of the compounds extracted from Potentilla anserina L., exhibited significant pharmacological activity against oxidative stress and hypoxic injury in our previous study. However, the effect of rosamultin on bone damage induced by acute hypobaric hypoxia (HH) has not been thoroughly studied. Methods: In this study, we first investigated the protective effect of rosamultin against bone damage in rats following acute exposure to simulated high-altitude hypoxia. Furthermore, we explored the detailed mechanism involved in the regulation of rat bone remodeling by rosamultin in an acute HH environment through analysis of sclerostin expression and the regulation of downstream signaling pathways. Results: Pretreatment with rosamultin significantly reduced HH-induced oxidative stress and inflammation, improved bone metabolic abnormalities, and alleviated the imbalance in bone remodeling in rats exposed to acute HH. Rosamultin markedly downregulated the expression of sclerostin, activated the Wnt/β-catenin signaling pathway, and enhanced the ratio of osteoprotegerin/receptor activator of nuclear factor kappa B ligand to maintain the balance of bone formation and resorption. Conclusions: Rosamultin attenuates acute HH-induced bone damage and improves abnormal bone remodeling in rats by inhibition of sclerostin expression and activation of the Wnt/β-catenin signaling pathway.

Symbiotic Effects of Kefir and Yacon Flour (Smallanthus sonchifolius) on Bone Remodeling in Rats

Abstract Objectives Kefir is a natural source of probiotics that confer benefits to the host's intestinal health. Yacon (Smallanthus sonchifolius) is a tuberous root originating in the Andes region, rich in prebiotic fructooligosaccharides (FOS), which increases the absorption of minerals. The objective of this study was to evaluate the prebiotic properties of yacon, the probiotic effect of kefir and the symbiotic action of the association between them in bone health in rats. Methods Adult Wistar rats were divided into 4 groups (n = 10): Group C (Control), Y (yacon flour, 51.34% FOS) K (kefir, 10⁷ UFC/mL), and YK (yacon flour + kefir). Group C received AIN-93 M + cow's milk (1 mL/day), group Y received AIN93 diet added by yacon flour to provide 5% FOS + cow's milk, group K received fermented kefir (1 mL/day), and group YK received yacon flour + fermented kefir. Feces and urine were collected for calcium balance in the last week of the experiment. At the end of 6 weeks, the animals were euthanized and the large intestine and blood sample were collected for analysis of intraluminal pH (pH meter Kasvi®) and biomarkers of bone remodeling, respectively. Calcium from diet, feces and urine was analyzed by atomic absorption. Osteocalcin (OC -- EL-R0243), C telopeptide of type I collagen (CTX – EL-R1456) and N telopeptide of type I collagen (NTX – EL-R0276) were analyzed by ELISA, according to manufacture's instructions (Elabscience, TX, USA). The results were analyzed by ANOVA, followed by the Tukey test (p &amp;lt; 0.05), using GENES®. Results No significant differences were observed between groups concerning calcium balance and cecal pH, although pH was slightly lower in the groups fed yacon (Y and YK). Biomarkers of bone formation (OC) and bone resorption (CTX and NTX) were significantly lower in group K (OC = 7.29; CTX = 4.04; NTX = 94.31 ng/mL), compared to the control (OC = 16.33; CTX = 5.68; NTX = 105.97 ng/mL). Groups Y (OC = 13.63; CTX = 5.13; NTX = 114.34 ng/mL) and YK (OC = 15.37; CTX = 5.17; NTX = 132.51 ng/mL) did not differ from the control. Conclusions Prebiotic (Y) and Symbiotic (YK) were more effective than kefir in bone remodeling in rats, although fermentation in the large gut did not reduce pH sufficiently to improve calcium absorption and retention. Funding Sources FAPES; CNPq and CAPES/Brazil.

Physical & mental activities enhance the neuroprotective effect of vinpocetine & coenzyme Q10 combination against Alzheimer & bone remodeling in rats

BackgroundAlzheimer's disease is a neurodegenerative disorder characterized by a progressive decline of cognitive abilities as well as bone loss. Physical and mental activities maintain cognitive functions as well as increase bone mass by inhibiting bone resorption. VIN and CoQ10 are neuroprotective drugs that possess anti-inflammatory and antioxidant properties. AimsTo study the effect of PH&M on enhancing the neuroprotective role of VIN and CoQ10 combination during induction of AD model in rats besides their role against bone mass loss associated with AD model. Main methodsSix groups of rats were received saline, AlCl3, and PH&M daily either alone or with a combination of VIN and CoQ10 for 4 weeks. Various biochemical analyses were performed to evaluate the extent of brain damage such as ACHE, β-secretase, chitinase, Aβ, tau protein, and monoamines besides the inflammatory and antioxidant parameters. Serum levels of minerals as well as 25-OHD, PTH, RANKL, and OPG levels were measured to detect the extent of bone impairment. Also, histopathological changes were evaluated in different brain regions and hind paw. Key findingsVIN and CoQ10 combination together with PH&M significantly attenuated the neurodegeneration induced by AlCl3 administration through the improvement of AD markers in brain tissue as well as oxidant and inflammatory markers. Bone resorption markers, serum minerals, and PTH levels were also normalized too. SignificanceNeuroprotective drugs together with PH&M have a more protective effect against AD and bone loss rather than PH&M alone.

Dynamic Evaluation of Orthodontically-Induced Tooth Movement, Root Resorption, and Alveolar Bone Remodeling in Rats by in Vivo Micro-Computed Tomography.

BackgroundThe aim of this study was to dynamically evaluate tooth movement, root resorption, and remodeling of alveolar bone using different forces to cause tooth movement in rats.Material/Methods12-week-old male Sprague-Dawley rats were selected. Nickel-titanium (Ni-Ti) coil springs (20 g, 50 g, and 100 g forces) were placed for mesial movement of the left first maxillary molar teeth. Tooth movement, root resorption, and microarchitectural parameters of the trabecular bone were evaluated by in vivo micro-CT. Histological examination was used to observe the root resorption, alveolar bone remodeling, and changes in osteoclasts from day 0 to day 14.ResultsThe tooth movement distance increased significantly over the initial 3 days in the 3 groups. The 20 g force group showed more tooth movement than in the 50 and 100 g force groups after 14 days (P<0.05). From days 7 to 10, root resorption lacunae appeared in the 3 groups and then stabilized, and the 100 g force group produced more lacunar resorption than in the anther 2 groups (P<0.05). Compared to day 0, the trabecular thickness and bone volume fraction on the pressure side gradually decreased from day 7 to day 14. The structure model index increased significantly from day 3 to day 14. Histological examination showed remarkable root resorption craters and osteoclasts positive for tartrate-resistant acid phosphatase in the root resorption lacunae in the 50 g and 100 g groups from day 7 to day 14.ConclusionsA 100 g heavy force can be used to establish a root resorption model in rats.

The effects of alveolar decortications on orthodontic tooth movement and bone remodelling in rats.

Alveolar decortication (AD) is a minimally invasive procedure that can be performed in the orthodontic office as an intervention to accelerate tooth movement. There is a gap in the literature evaluating the earlier and delayed responses after AD using lighter orthodontic forces in a rat model. Therefore, the aim of this study was to determine the effects of AD in the amount of orthodontic tooth movement and on alveolar bone remodelling in a rodent model, after 7 or 14 days. A total of 32 15-week-old male Wistar rats were used in four treatment groups: (1) orthodontic spring only (7 days), (2) orthodontic spring only + AD (7 days), (3) orthodontic spring only (14 days), and (4) orthodontic spring only + AD (14 days). A closed coil nickel-titanium spring delivering 8-10 g of force was used to move the molar mesially. Alveolar decortication was done using a high speed, quarter round bur adjacent to the left first maxillary molar, on the palatal alveolar bone. At each endpoint, rats were sacrificed and microfocus computed tomography and histological analysis were performed. The spring + AD group presented with a significant increase in the rate of tooth movement when compared with spring only group, 7 and 14 days after the beginning of the experiments. In addition, the spring + AD group had a significant decrease in bone volume and tissue density and a significant increase in the trabecular spacing and the number of osteoclasts at 7 and 14 days. Furthermore, a fibrous tissue was found to replace the alveolar bone in the spring + AD group at day 14. Alveolar decortications enhanced bone remodelling around the tooth movement region and could be used as an adjunct surgical procedure to accelerate the rate of tooth movement.

Protective effect of ethanolic extract of Urtica urens L. against the toxicity of imidacloprid on bone remodeling in rats and antioxidant activities

Imidacloprid (IMI) is very harmful to human health and cause problems. Recently, plants have been considered as potential agents for protection against these disorders. Urtica urens L. (UU) is very useful for relieving rheumatic pains and there is no scientific evidence justifying its use, which lets us think of its direct effect on the bone. This study aimed to investigate the protective effect of UU against toxicity effects of IMI in female rat. Rats were divided into control group, 3 groups treated with IMI at 50, 200 or 300mg/kg/day and 3 groups co-treated with IMI (50, 200 or 300mg/kg/day)+100mg/kg/day of UU. We studied bone remodeling through histological, histomorphometry and biochemical analyses.In IMI- treated groups, we have noted, following histomorphomotric analysis, significant decreases in cortical, trabecular thicknesses and osteoid surfaces. Elsewhere, IMI intoxication significantly decreased serum vitamin D and hydroxyproline levels in the groups treated for 60days. IMI intoxication increased significantly calcium, phosphorus contents, MDA and AOPP levels and the rate of calcification. It decreased significantly GSH, GPx, SOD, CAT, 17b-Estradiol and vitamin E levels, induces a tendency of rarefaction and increases of intrabecular spaces. The co-treatment with UU improved all biochemical parameters (hydroxyproline, MDA, AOPP, GSH, GPx, SOD, CAT, 17b-Estradiol, vitamin D, vitamin E calcium, phosphorus). UU leads to a significant increase in cortical, trabecular thicknesses, osteoid surfaces, a decrease in the intrabecular spaces and the rarefaction of bone.In conclusion, IMI inhibits bone remodeling and enhances bone formation. A significant antioxidant activity was also observed in UU and a total of 6 compounds were identified. Co-administration of UU provided a significant protection which might be due to its antioxidant property.

Experimental tooth movement and photobiomodulation on bone remodeling in rats.

Photobiomodulation (PBM) is a therapy induced by a specific type of laser that affects biologic systems through non-thermal ways. The study of its basic mechanism has gained interest since little is known about the causes of the different effects of this treatment. In the present study, we investigated the action of the PBM application rate changes in the peri-implant tissues in rats subjected to tooth movement in different periods. Wistar rats (±250g) received an apparatus in the region of the central incisors superiors tightly (70g) or not, and they were also subjected to one or three PBM sessions. After 7 or 14days, the rats were subjected to euthanasia and the jaws were dissected and processed for histology. For analysis, serial sections were made that were stained by Picrosirius Red for analysis of collagen fibers, Masson's trichrome for newly formed bone scan, and Hematoxylin-Eosin for quantification of osteoblasts. PBM applied in one or three sessions increased the population of osteoblasts. Still, the application of three sessions of PBM increased the density of collagen fibers and new bone formation compared to the controls. An increase was observed in the interincisal distance in irradiated groups with three PBM sessions and the application of force for both 7 or 14days. These findings suggest that PBM can contribute positively to the orthodontic movement. So the laser therapy can be used as an adjunct procedure to be performed concurrently for orthodontic treatment in the dental clinic.

Application of coenzyme Q10 for accelerating soft tissue wound healing after tooth extraction in rats.

Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10), may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old) (n = 27) received topical application of ointment containing 5% rCoQ10 (experimental group) or control ointment (control group) to the sockets for 3 or 8 days (n = 6–7/group). At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p < 0.05). Gene expression of interleukin-1β, tumor necrosis factor-α and nuclear factor-κB were also lower in the experimental group than in the control group (p < 0.05). At 8 days after tooth extraction, there were no significant differences in collagen density, number of polymorphonuclear leukocytes and bone fill between the groups. Our results suggest that topical application of rCoQ10 promotes wound healing in the soft tissue of the alveolar socket, but that rCoQ10 has a limited effect on bone remodeling in rats.

A novel technique for the measurement of bone remodeling in rats

A novel technique for the measurement of bone remodeling in rats