雄激素对大鼠牙槽骨骨量的影响

目的：探讨去睾丸对大鼠牙槽骨骨量的影响。方法：24只雄性SD大鼠随机分为3组：假手术组（Con）、去睾丸组（ORX）和雄激素治疗组（TP）。除Con组外,其余行双侧睾丸摘除术。Con组和ORX组给予溶媒5ml/kg/d灌胃,TP组给予丙酸睾丸酮5mg/kg/d灌胃。实验12周后取大鼠的牙槽骨,脱钙,切片,染色,用骨形态计量学方法测量牙槽骨松质骨的骨量,计算牙槽骨的骨静态学参数。结果：与Con组相比较,ORX组牙槽骨骨小梁厚度降低（P〈0.05）,其他变化均不明显。结论：雄激素缺乏使大鼠牙槽骨有丢失趋势,但不明显。     

丹参素防治去卵巢大鼠牙槽骨骨量的丢失

目的:探讨丹参素对大鼠牙槽骨骨量的影响、丹参素与雌激素防止牙槽骨骨丢失的疗效比较以及丹参素与雌激素是否具有防止牙槽骨骨丢失的协同效应.方法:40只SD大鼠随机分为5组:假手术组(Sham)、去卵巢组(OVX)、雌激素组(E2)、丹参素(Tan)及丹参素与雌激素联合用药组(E2 Tan).雌激素组、丹参素组和丹参素与雌激素联合用药组分别用雌激素100 μg·kg-1·d-1、丹参素12.5 mg·kg-1·d-1和丹参素12.5 mg·kg-1·d-1加雌激素50 μg·kg-1·d-1给大鼠灌胃,17欠/d,共90 d.实验90 d后取大鼠的牙槽骨,脱钙,切片,染色,用骨形态计量学方法测量牙槽骨松质骨的骨量,计算牙槽骨的骨静态参数.结果:与假手术组相比,去卵巢组牙槽骨骨小梁面积百分数减小(P＜0.01)和骨小梁分离度增大(P＜0.05).与去卵巢组相比,雌激素组牙槽骨骨小梁面积百分数、骨小梁厚度均增大(P＜0.01),丹参素组及联合用药组牙槽骨骨小梁面积百分数增大(P＜0.05).与丹参素组相比,雌激素治疗组及联合用药组各项测量指标差别均没有统计学意义.结论:丹参素都能防治牙槽骨骨质疏松且疗效与雌激素相当,但丹参素与雌激素在防治牙槽骨骨质疏松时没有协同作用.     

高脂饮食对大鼠下颌骨钙﹑磷及羟脯氨酸含量以及对牙槽骨骨量的影响

目的:探讨高脂饮食与大鼠下颌骨钙、磷及羟脯氨酸含量以及牙槽骨骨量的关系.方法:将20只SD大鼠随机分为正常对照组和脂肪乳剂组,正常对照组予普通饲料及生理盐1 mL/100 g体重灌胃,脂肪乳剂组予普通饮食加脂肪乳剂1 mL/100 g体重灌胃,两组均连续灌胃16周后取大鼠的下颌骨下颌支部分检测骨钙、磷及羟脯氨酸含量,取牙槽骨进行脱钙、切片、苏木精-伊红染色,然后用骨形态计量学方法测量牙槽骨松质骨的骨量并计算牙槽骨的骨静态参数.结果:高脂饮食引起大鼠血清中总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-c)明显升高,而高密度脂蛋白胆固醇(HDL-c)则明显降低;脂肪乳剂灌胃使大鼠下颌骨钙﹑磷及羟脯氨酸含量均下降(P<0.05).与对照组相比,模型组牙槽骨骨小梁面积百分数(Tb.Ar)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)和骨小梁分离度(Tb.Sp)差异均无统计学意义.结论:长期高脂乳剂灌胃可以造成大鼠下颌骨骨矿物质和骨有机质的丢失,但未能引起大鼠牙槽骨骨量发生明显变化.     

高脂饮食对大鼠下颌骨钙、磷及羟脯氨酸含量以及对牙槽骨骨量的影响

目的:探讨高脂饮食与大鼠下颌骨钙、磷及羟脯氨酸含量以及牙槽骨骨量的关系。方法:将20只SD大鼠随机分为正常对照组和脂肪乳剂组,正常对照组予普通饲料及生理盐1mL/100g体重灌胃,脂肪乳剂组予普通饮食加脂肪乳剂1mL/100g体重灌胃,两组均连续灌胃16周后取大鼠的下颌骨下颌支部分检测骨钙、磷及羟脯氨酸含量,取牙槽骨进行脱钙、切片、苏木精-伊红染色,然后用骨形态计量学方法测量牙槽骨松质骨的骨量并计算牙槽骨的骨静态参数。结果:高脂饮食引起大鼠血清中总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-c)明显升高,而高密度脂蛋白胆固醇(HDL-c)则明显降低;脂肪乳剂灌胃使大鼠下颌骨钙?磷及羟脯氨酸含量均下降(P<0.05)。与对照组相比,模型组牙槽骨骨小梁面积百分数(Tb.Ar)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)和骨小梁分离度(Tb.Sp)差异均无统计学意义。结论:长期高脂乳剂灌胃可以造成大鼠下颌骨骨矿物质和骨有机质的丢失,但未能引起大鼠牙槽骨骨量发生明显变化。     

紫苏籽油对实验性牙槽骨骨质疏松的作用研究

目的：探讨紫苏籽油对去卵巢大鼠牙槽骨丢失的影响研究。方法：SD大鼠随机分为3组：对照组、去卵巢组和紫苏籽油治疗组。实验90d后取大鼠牙槽骨,测量牙槽骨组织形态计量学参数。结果：与去卵巢组相比：紫苏籽油治疗组牙槽骨骨量明显增多,%Tb.Ar升高34.47%（P〈0.05）,Tb.Th增加36.99%（P〈0.01）。结论：紫苏籽油能抑制去卵巢大鼠牙槽骨丢失。     

牙齿移动过程中牙槽骨显微结构动态变化的微型CT研究

目的 通过微型CT探讨正畸牙齿移动过程中矫治力对牙槽骨骨小梁的影响规律,以期为正畸临床提供参考.方法 选择10周龄SD雄性大鼠10只建立实验动物模型,施加0.196 N矫治力,近中移动上颌第一磨牙,分别于加力前、加力后第3、7、14 d对大鼠上颌牙槽骨骨小梁进行微型CT扫描,计算骨体积分数、骨表面积体积比、结构模型指数...     

大鼠双侧卵巢切除术后下颌剩余牙槽骨骨小梁的结构变化

本实验切除64只SD雌性大鼠双侧卵巢并拔除全部磨牙后,应用扫描电镜(SEM)和MIAS—200图象分析系统,动态地观察了失牙后各程期(1—8月)大鼠剩余牙槽骨骨小梁结构变化,以及与股骨骨小梁变化的关系。结果表明:雌激素低下使大鼠剩余牙槽骨骨量减少,实质是骨小梁体密度减少。早期以骨小梁板厚度减少为主,后期以骨小梁板密度减少为主。股骨骨量丧失是骨小梁板密度和板厚度共同减少所致。股骨骨小梁体密度减少与剩余牙槽骨体密度减少密切相关,说明后者为全身性骨量改变的局部口腔表现。     

不同去势时间大鼠牙槽骨微结构变化的Micro-CT研究

目的： 观察不同去势时间大鼠牙槽骨微结构的改变,探讨去势时间对牙槽骨骨质疏松程度的影响。方法： 健康未孕雌性SD大鼠24只,随机分为去势组(OVX)与假手术组（sham）,每组各12只,分别在全麻下行双侧卵巢去势术与假手术。于术后3个月及6个月2个不同时间点分别处死每组大鼠各6只,取右侧上颌骨标本行Micro-CT扫描;观察去势3个月及6个月后大鼠上颌第一磨牙根分叉区牙槽骨微结构的改变。采用SPSS16.0软件包对数据进行统计学分析。结果： Micro-CT水平面、矢状面二维图像及三维重建均显示,去势3个月及6个月大鼠牙槽骨骨髓腔面积增加、骨小梁变细、部分发生断裂。骨结构参数分析显示,去势3个月及6个月后,大鼠牙槽骨骨密度（BMD）及骨体积分数（BV/TV）、骨小梁宽度（Tb.Th）均显著低于相应时间假手术大鼠（P<0.05）;去势6个月组较3个月组大鼠牙槽骨骨密度(BMD)、骨体积分数(BV/TV)、骨小梁宽度(Tb.Th)显著降低（P<0.05）。去势3个月及6个月大鼠骨小梁数目（Tb.N）及骨小梁分离度（Tb.Sp）显著高于相应假手术组（P<0.05）,且去势6个月组骨小梁数目(Tb.N)显著高于去势3个月组（P<0.05）。结论： 随着去势时间延长,大鼠牙槽骨骨量降低、骨小梁微结构破坏加剧,骨质疏松程度加重。     

尼古丁对实验性牙周炎大鼠牙槽骨影响的显微CT观察

目的 建立牙周炎大鼠的牙槽骨三维模型,采用显微CT观察尼古丁对大鼠牙槽骨的影响.方法 36只SD大鼠,丝线结扎上颌右侧(实验侧)第二磨牙颈部,左侧不予结扎,作为自身对照(对照侧),使用完全随机分组方法分为对照组(A)及尼古丁注射低剂量(B)和高剂量(C)组,每组12只.分别给予生理盐水和尼古丁0.83、1.67 mg·kg-1·d-1腹腔注射.每组分别于给药后第14、28天各处死6只,取双侧上颌磨牙区牙体牙周复合组织,行显微CT扫描、重建、测最和分析.结果 随尼古丁给药剂量增加,双侧牙槽骨骨密度、骨体积分数、骨小梁厚度逐渐降低,牙槽骨高度丧失与骨小梁间隙逐渐升高.28 d时C组牙槽骨高度丧失[对照侧和实验侧分别为(0.61±0.14)、(1.39±0.09)mm]显著高于B组[对照侧和实验侧分别为(0.39±0.10)、(1.31±0.06)mm]和A组[对照侧和实验侧分别为(0.30±0.06)、(0.94±0.07)mm];C组牙槽骨骨密度[对照侧和实验侧分别为(617.86±34.27)、(572.46±31.62)mg/cm3]显著低于B组[对照侧和实验侧分别为(660.04±36.73)、(604.97±32.59)mg/cm3]和A组[对照侧和实验侧分别为(709.15±34.95)、(657.04±30.06)mg/cm3].结论 尼古丁可加重丝线结扎造成的大鼠牙槽骨骨量丧失和骨质微观结构的变化,导致牙槽骨骨质疏松.     

大豆异黄酮预防绝经后牙槽骨骨质疏松的动物实验

目的:探讨大豆异黄酮对绝经后牙槽骨骨质疏松的防治作用。方法:将32只3月龄雌性SD大鼠随机分为4组,适应性喂养1周后,A组为假手术组,B、C、D组均摘除双侧卵巢。C组大鼠于术后1周开始肌肉注射苯甲酸雌二醇(0.1mg/kg),每周1次。而A、B和D组肌肉注射等量橄榄油。D组大鼠于术后1周开始每天给予大豆异黄酮混悬液灌胃(100mg/kg)。其余3组用等量生理盐水灌胃。各组动物在同等条件下饲养,自由进食、饮水。实验结束后处死动物,收集大鼠下颌骨标本。对组织HE染色切片进行骨形态及计量学分析。结果:去卵巢后,大鼠牙槽骨呈疏松样改变。大豆异黄酮治疗后的D组.骨小梁面积、骨小梁周长、骨小梁面积比、骨小梁数量及分离度与去卵巢的B组有显著性差异,而与雌激素治疗的C组无显著性差异。结论:雌激素缺乏可引起牙槽骨骨质疏松。大豆异黄酮与雌激素一样。可以抑制破骨细胞性骨吸收.并对骨形成有刺激作用。     

Short-term etidronate treatment prevents glucocorticoid-induced bone debility of the mandible in growing rats

Authors – Fujita Y, Konoo T, Maki K Objectives – To analyse the effects of short‐term treatment with etidronate on the glucocorticoid‐induced retardation of bone growth and deterioration of bone structure in the prepubertal rat mandible. Materials and Methods – Fifty 5‐week‐old male rats were divided into five groups. Etidronate or vehicle treatment (5 mg/kg/day, daily, subcutaneous injection) was initiated after glucocorticoid administration (30 mg/kg/day, on alternate days, orally) for 6 weeks and was continued for 3 weeks. Then, bone growth was measured using lateral cephalometric analysis. Peripheral quantitative computed tomography was used to determine bone density, bone cross‐sectional area and bone strength. Results – Glucocorticoid‐treated rats had significantly lower body weight, mandibular length, cortical bone density, bone strength and cross‐sectional area in trabecular and cortical bone, but had significantly higher trabecular bone density than untreated rats. No significant difference in mandibular height was observed between the glucocorticoid‐treated group and the untreated control group. Etidronate treatment improved the glucocorticoid‐induced decrease in bone strength and increased density in trabecular and cortical bone above the untreated control level, but had no significant effects on the reduction in mandibular length. Conclusion – These findings suggest that etidronate can potentially reverse the glucocorticoid‐induced deterioration of internal bone structure, but has no beneficial effects on the glucocorticoid‐induced retardation of bone growth in the growing rat mandible.     

Sex and age differences in bone morphology of mandibles.

Histomorphometric analysis of mandibular specimens has been performed in order to demonstrate possible sex and age differences in percent bone mass and bone activity in the mandible. The material consisted of 32 autopsy specimens from the right premolar region of the mandibular body in subjects with sudden unexpected death and without known bone disease. The subjects were divided in a young group (20--43 years of age) and an old group (60--90 years of age); each group consisted of eight females and eight males. Microradiograms of buccolingual ground sections of 100 micron were used. Quantitation of (1) percent bone area of cortical and trabecular bone and (2) total bone surface/bone area and resorption surfaces/total bone surface in trabecular bone, were done by electronic point-counting. The analysis did not reveal any significant sex or age differences in the trabecular bone with respect to percent bone mass, trabecular coarseness and bone activity. In the buccal and lingual cortices a significant age difference was demonstrated, but there was no sex difference in percnet bone mass. Cortical porosity in mandibles clearly increases with increasing age, but seems to be independent of sex.     

Sex and age differences in bone morphology of mandibles

abstract — Histomorphometric analysis of mandibular specimens has been performed in order to demonstrate possible sex and age differences in percent bone mass and bone activity in the mandible. The material consisted of 32 autopsy specimens from the right premolar region of the mandibular body in subjects with sudden unexpected death and without known bone disease. The subjects were divided in a young group (20–43 years of age) and an old group (60–90 years of age); each group consisted of eight females and eight males. Microradiograms of buccolingual ground sections of 100 μm were used. Quantitation of (1) percent bone area of cortical and trabecular bone and (2) total bone surface/bone area and resorption surfaces/total bone surface in trabecular bone, were done by electronic point-counting. The analysis did not reveal any significant sex or age differences in the trabecular bone with respect to percent bone mass, trabecular coarseness and bone activity. In the buccal and lingual cortices a significant age difference was demonstrated, but there was no sex difference in percent bone mass. Cortical porosity in mandibles clearly increases with increasing age, but seems to be independent of sex.     

唑来磷酸对实验性牙槽骨吸收抑制作用的研究

目的:在实验性牙槽骨吸收动物模型基础上,研究唑来磷酸局部应用对实验性牙槽骨吸收的影响,旨在找出一种效果理想的防治牙槽骨吸收的局部应用药物,为其局部应用于临床提供实验依据。方法:40只SD大鼠,随机分为5组,每组8只,一组为正常对照组,其余4组为实验组,分别为造模对照组、唑来磷酸低剂量、中剂量和高剂量治疗组(0.8mg/mL,1.0mg/mL和1.2mg/mL);实验组均采用牙周翻瓣术建立牙槽骨吸收模型,治疗组在翻瓣局部处分别给予不同浓度的唑来磷酸药物。所有大鼠在给药21天后处死,取牙体牙周组织标本,进行X线片拍摄、常规病理切片观察。结果:低剂量组、中剂量组和高剂量组牙槽骨吸收程度明显低于造模对照组,差异有统计学意义(P<0.05);牙槽骨病理切片显示中剂量组和高剂量组破骨细胞数量均较造模对照组明显减少(P<0.05);且骨小梁面积均优于造模对照组(P<0.05)。结论:唑来磷酸局部应用对牙周翻瓣术诱导的牙槽骨吸收具有一定的抑制作用。     

A histomorphological investigation of the effect of cyclosporin on trabecular bone of the rat mandibular condyle

The effect of cyclosporin A (CSA) on the condylar trabecular bone was evaluated by microscopy. Twenty, 5-week-old male Sprague–Dawley rats were divided into a treated and a control group. Animals in the treated group received CSA, 15 mg/kg body weight, by gastric feeding daily for 4 weeks; controls received the vehicle only. Five animals from each group were killed at the end of weeks 2 and 4. After histological processing, 10 tissue sections from the mid-part of the mandibular condyle were examined. Generally, a histopathological osteopenia was observed around the condyle after CSA treatment, especially at the end of week 4. In the control animals, the trabecular bone volume steadily increased from weeks 2 to 4 (from 0.46±0.07 to 0.61±0.07 mm³/mm³). However, the bone volume was significantly less in the CSA group than in the control group at both times (0.33±0.02 vs 0.46±0.07 and 0.26±0.07 vs 0.61±0.07 mm³/mm³ for CSA vs control group at the end of weeks 2 and 4, respectively). Conversely, an increased marrow volume was observed in the CSA group at both these times (0.60±0.02 vs 0.42±0.08 and 0.71±0.06 vs 0.31±0.06 mm³/mm³ for CSA vs control group at the end of weeks 2 and 4, respectively). Decreases were also observed in trabecular thickness, osteoid seam width, osteoid volume and cortical bone width. Because trabecular bone mass, osteoid mass and cortical bone thickness all showed a decrease after CSA at both times, an inhibitory effect of CSA on trabecular bone formation in the mandibular condyle is proposed.     

Microarchitecture of medication-related osteonecrosis of the jaw (MRONJ); a retrospective micro-CT and morphometric analysis

Medication-related osteonecrosis of the jaw (MRONJ) is a severe side effect of antiresorptive (AR) drugs such as bisphosphonates (BP) and denosumab (Dmab). Although several risk factors are described, the etiology of MRONJ is still not fully elucidated. Bone-strengthening is the primary aim of antiresorptive therapy; however, overly increased bone mass and microcrack accumulation are also discussed in MRONJ etiologies. The aim of this study is to evaluate the microarchitecture of jaw bones with micro?computed tomography (micro-CT) in AR-treated patients with or without MRONJ.Human jaw bone samples of AR-treated patients were separated into 11 groups by AR treatment bisphosphonate (BP), denosumab (Dmab), both (M) and control groups. Subgroups were divided according to the clinical localization as AR-exposed vital jaw bone (BP_exp, Dmab_exp, M_exp), osteonecrosis–margin of a sequestrum (BPO_mar, DmabO_mar, MO_mar) and osteonecrosis–sequestrum (BPO_seq, DmabO_seq, MO_seq). Healthy jaw bone (C_HB) and osteoporotic jaw bone (C_OP) represent control groups. Samples underwent retrospective micro-CT and morphometric analysis in representative units by bone volume fraction (BV/TV), bone surface density (BS/BV), trabecular thickness (Tr.Th.), trabecular number (Tr.N.), trabecular space (Tr.Sp.), Euler characteristic for bone connectivity, bone mineral density (BMD) and tissue mineral density (TMD).A total of 141 samples from 78 patients were analyzed. BV/TV of M_exp group (mean: 0.46 ± 0.27) was significantly higher than in the C_OP group (mean: 0.14 ± 0.05; p = 0.0053). Tr.Th. differed significantly between the BP_exp group (mean: 0.32 ± 0.15) and the M_exp group (mean: 0.57 ± 0.20; p = 0.0452) as well as between the BPO_seq group (mean: 0.25 ± 0.10) and the MO_seq group (mean: 0.39 ± 0.18; p = 0.0417). Signs of trabecular thickening and unorganized trabecular microarchitecture from AR-exposed- to sequestrum groups, were analyzed in 3D reconstructions. However, BS/BV, Tr.N., and Tr.Sp. showed no significant differences. Euler characteristic of the BPO_seq group (median: 7.46) doubled compared to that of the BP_exp group (median: 14.97; p = 0.0064). Mineralization parameters BMD and TMD were similar in all groups.Findings show evidence of enhanced bone mass and suspect microarchitecture in some AR-treated jaw bone compared to osteoporotic jaw bone. Despite increased bone mass, some MRONJ samples showed decreased trabecular connectivity by Euler characteristic compared to AR-treated jaw bone. These samples may indicate extensive ossification and ineffective bone mass with superficially higher bone mass without existing or even reduced mechanical stability, indicated by connectivity loss. This result might also suggest a high risk to microcrack accumulation. At some point, possibly some kind of over-ossification could lead to under-nourishment and microarchitectural weakness, creating instability, subsequently increasing vulnerability to MRONJ.     

Effects of chitosan oligosaccharides on the femur trabecular structure in ovariectomized rats

Objectives Drugs used to treat osteoporosis are taken long-term and ideally have no adverse effects. Recent interest has focused on chitosan oligosaccharides as a bone-inducing substance for use as bone graft material. The present study was designed to investigate the effects of chitosan oligosaccharides on the femur trabecular structure in ovariectomized rats by three-dimensional imaging analysis using micro-computed tomography (CT).Methods Female 12-week-old Wistar rats were divided into three groups, which underwent ovariectomy (two groups) or sham surgery (one group). After 12 weeks, rats of one of the ovariectomized groups began treatment with chitosan oligosaccharides (500 mg/kg bodyweight) three times per week for 8 weeks. Then, the femurs of all rats were resected for bone analysis by micro-CT, and three-dimensional images of the femur were reconstructed from the axial CT images to evaluate the following parameters: bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.sp), trabecular bone pattern factor (TBPf), structure model index (SMI), number of nodes per unit tissue volume, number of termini per unit tissue volume, and the total strut length per unit tissue volume.Results The BV/TV, Tb.Th, and Tb.N were significantly higher in the ovariectomized and treated (OVX + C) group versus the ovariectomized, untreated (OVX) group. Tb.Sp, TBPf, and SMI were significantly lower in the OVX + C group versus the OVX group.Conclusions Our findings demonstrate that chitosan oligosaccharides prevent decreases in bone volume, trabecular number, trabecular thickness, and trabecular connectivity in the femurs of ovariectomized rats.     

Changes in bone mass in rat mandibles after tooth extraction.

An experimental study concerning changes in bone mass in trabecular bone of mandibles on rats after extractions of upper molars has been carried out. The material consisted of 32 SPF Wistar rats, fed on Nafag-184 only. Experimental and control groups consisted of eight females and eight males, each group having same average weight with respect to sex at the age of 16 weeks. At this age the upper right molars were extracted on all rats in the experimental group. The rats were sacrificed after 16 weeks. Identical increase in weight within each sex group was found. Microradiograms of two buccal-lingual 100-mu-thick ground sections at a distance of 0.5 mm through the first molar in each side of the mandible were used. Quantitation of bone mass (bone area in percent) of a trabecular bone was done by electronic point counting. No significant difference in bone mass was found between left and right sides in the control group (P greater than 0.50), whereas a significant difference was found between left and right sides in the experimental group (P approximately 0.0001) with lowest mean value in right sides. Conclusively the analysis shows that local reduction in bite force causes osteoporotic changes in trabecular bone of the jaw.