糖尿病牙周炎模型大鼠的牙槽骨丧失

背景：糖尿病牙周炎大鼠与单纯慢性牙周炎大鼠以及正常对照组大鼠在不同时间段内体质量、血糖、牙周组织的变化对牙槽骨丧失程度的影响不同。 目的：建立糖尿病牙周炎模型大鼠和慢性牙周炎模型大鼠,观察糖尿病加重牙周炎大鼠槽骨吸收的破坏程度。 方法：选用8周龄SPF级雄性SD大鼠52只,随机分为糖尿病牙周炎组、慢性牙周炎组以及正常对照组。糖尿病牙周炎组大鼠按采用注射链脲佐菌素+牙周结扎的方法建立糖尿病牙周炎模型大鼠。慢性牙周炎组大鼠采用牙周结扎并不断加压的方法建立慢性牙周炎大鼠模型;正常对照组大鼠正常喂养。各组大鼠分别于结扎后1,2,3,4周,观察各组大鼠牙周组织变化,取上颌骨牙槽骨标本,在体视显微镜下观察各组大鼠牙槽骨丧失值程度。 结果与结论：钢丝结扎后1,2,3,4周大鼠牙槽骨丧失程度：糖尿病牙周炎组>慢性牙周炎组>正常对照组(P < 0.05)。结果证实,实验成功建立糖尿病牙周炎和慢性牙周炎动物模型,糖尿病可加重牙周炎牙周组织破坏,牙槽骨丧失增加。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

吸烟促进牙周炎牙槽骨的吸收效应

背景：多项研究证实吸烟能够促进牙周炎性牙槽骨吸收。 目的：观察吸烟在牙周炎性牙槽骨吸收大鼠中的作用。 方法：24只大鼠随机分为3组,正常组：正常饲养,不给予其他处理;对照组：采用钢丝结扎法建立大鼠实验性牙周炎动物模型;实验组：在造模期间给予被动吸烟。8 周后将所有大鼠处死,取出牙周组织,利用苏木精-伊红染色观察牙周组织的病理学改变,运用免疫组织化学染色观察核因子活化因子受体配体和骨保护素的表达变化。 结果与结论：对照组和实验组大鼠造模8周后,实验组大鼠牙槽骨中核因子κB受体活化因子配体表达量高于对照组(P < 0.05),而对照组大鼠牙槽骨中骨保护素的表达量较实验组有明显上调(P < 0.05)。提示吸烟能够提高牙周炎大鼠核因子κB受体活化因子配体的表达,同时并可以降低骨保护素的表达变化,在一定程度上加重了牙周炎性牙槽骨的吸收。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

黄芩素调控 NLRP3 / Caspase-1 通路对牙周炎大鼠牙槽骨吸收的影响

目的 探索黄芩素调控核苷酸结合寡聚化结构域样受体蛋白 3 ( nucleotide-binding oligomerizationdomain-like receptor protein 3, NLRP3) / 半胱氨酸天冬氨酸蛋白酶 1 ( cysteine aspartate protease 1, Caspase1) 通路对牙周炎大鼠牙槽骨吸收的影响。 方法 将 40 只牙周炎大鼠随机分为模型组、 黄芩素组、 激活剂组、 黄芩素 + 激活剂组, 另取 10 只正常作为对照组。 检测大鼠釉牙骨质界到牙槽嵴顶 (CEJ-AC) 的距离、血清中白细胞介素-6 (IL-6)、 转化生长因子-β (TGF-β) 含量以及牙周组织病理变化、 IL-6、 TGF-β 阳性表达和 NLRP3、 Caspase-1 蛋白表达。 结果 模型组大鼠 CEJ-AC、 NLRP3、 Caspase-1、 IL-6、 TGF-β 水平及阳性表达水平以及蛋白表达水平均升高 (P< 0. 05); 经黄芩素干预后, 各项指标均降低 (P< 0. 05); 引入激活剂明显削弱了黄芩素对牙周炎大鼠的抗炎作用。 结论 黄芩素通过抑制 NLRP3 / Caspase-1 通路减轻炎性反应, 控制牙槽骨吸收。     

去卵巢大鼠骨组织的变化

目的:观察去卵巢对大鼠骨组织的改变,以建立妇女绝经后骨质疏松的动物模型。方法:选用3月龄SD雌性大鼠16只,随机分为对照组和去卵巢组。去卵巢组大鼠的双侧卵巢被切除,对照组做假手术,持续90天。用骨矿测定仪测量大鼠股骨的骨密度及在半自动图像分析仪观测胫骨近端骨小梁的静、动态指标,并在扫描电镜下观察大鼠股骨松质骨结构的改变。结果:与对照正常组比较,去卵巢组大鼠股骨的远端的骨密度降低(P<0.05)。胫骨骨小梁的面积减少,骨小梁间隙增大。股骨的骨小梁变少,变细,断裂,连接不紧密,表面常见骨吸收形成的陷窝。结论:用切除卵巢的方法造成雌激素缺乏,导致骨质疏松,作为研究因绝经引起的原发性骨质疏松的可靠动物模型。     

去卵巢骨质疏松模型大鼠的番茄红素干预

背景：有研究表明番茄红素作为一种抗氧化物质能够减低患慢性疾病的风险。 目的：建立去卵巢骨质疏松大鼠模型,通过给去卵巢大鼠灌服不同剂量的番茄红素,观察其对实验性骨质疏松的保护作用。 方法：切除6月龄SPF级雌性Wistar 未生育大鼠双侧卵巢1周,建立去卵巢骨质疏松大鼠模型,分别给予苯甲酸雌二醇,番茄红素10 mg,20 mg进行干预。 结果与结论：各组给药12周后,番茄红素   高低剂量组与卵巢切除组比较子宫质量,血清中的钙、磷含量,骨小梁面积百分比,骨小梁数目增加,血清中超氧化物歧化酶活性,骨密度和骨生物学性能均明显增高       (P < 0.05);血清中碱性磷酸酶,尿中脱氧吡啶啉,丙二醛,骨小梁分离度和破骨细胞数均减少(P < 0.05)。结果证实,番茄红素能明显缓解去卵巢引起的子宫萎缩,清除体内的自由基,改善去卵巢大鼠的氧化应激状态,减少骨吸收增加骨形成。      

芹菜素治疗去卵巢骨质疏松模型大鼠的作用与剂量

文题释义： 芹菜素：主要存在于瑞香科、马鞭草科、卷柏科植物中,如芫花,卷柏中含量较大。芹菜素属于黄酮类,具有抑制致癌物质的致癌活性;作为治疗HIV和其他病毒感染的抗病毒药物;MAP激酶的抑制剂;治疗各种炎症;抗氧化剂;镇静、安神;降压。与其他黄酮类物质(槲皮素、山奈黄酮)相比具有低毒、无诱变性等特点。 骨密度：全称是骨骼矿物质密度,是骨骼强度的一个重要指标,以g/cm³表示,是一个绝对值。在临床使用骨密度值时由于不同的骨密度检测仪的绝对值不同,通常使用T值判断骨密度是否正常。T值是一个相对值,正常参考值在-1和+1之间。当T值低于-2.5时为不正常。骨密度,是骨质量的一个重要标志,反映骨质疏松程度,预测骨折危险性的重要依据。 背景：研究证实芹菜素具有抗病毒、抗炎、抗氧化、镇静安神等功效。 目的：研究不同剂量芹菜素对大鼠骨质疏松的疗效并探讨其机制。 方法：实验方案经南方医科大学动物实验伦理委员会批准。成年雌性SD大鼠42只,通过卵巢切除法建立大鼠骨质疏松模型,实验分为7组,每组6只大鼠,分别为假手术组、芹菜素20,40,60和80 mg/kg组、对照组、阳性对照组。假手术组未摘除卵巢,阳性对照组每天灌胃烯雌酚(0.02 mg/kg)、维生素D和钙;对照组给予同等量纯净水皮下注射;芹菜素各组分别给予相应剂量的芹菜素皮下注射;1次/d,用药8周。分别检测干预后第4周和第8周大鼠股骨密度和血清中钙、磷、骨碱性磷酸酶、Ⅰ型前胶原氨基末端前肽、β-Ⅰ型胶原C-末端肽的水平。 结果与结论：①与对照组比较,芹菜素剂量为40,60和80 mg/kg时,大鼠的骨密度、血清中钙、磷在第4周和第8周时均较高(P < 0.05),Ⅰ型前胶原氨基末端前肽、β-Ⅰ型胶原C-末端肽、骨碱性磷酸酶较低(P < 0.05);②与阳性对照组比,芹菜素剂量为60 mg/kg和80 mg/kg时,大鼠的骨密度、血清中钙、磷和骨碱性磷酸酶、Ⅰ型前胶原氨基末端前肽、β-Ⅰ型胶原C-末端肽在第4周和第8周时均无明显差别(P > 0.05),剂量为 20 mg/kg和 40 mg/kg时,骨密度、血清中钙、磷、均比阳性对照组低(P < 0.05),Ⅰ型前胶原氨基末端前肽、β-Ⅰ型胶原C-末端肽比阳性对照组高(P < 0.05);③对照组和假手术组比较,在第4周和第8周时大鼠骨密度、 血清中钙、磷均比较低(P < 0.05),Ⅰ型前胶原氨基末端前肽、β-Ⅰ型胶原C-末端肽均比较高(P < 0.05);④结果说明,去卵巢法建立大鼠骨质疏松模型确实有效;芹菜素对骨质疏松的治疗作用和剂量相关,一定剂量的芹菜素具有类似烯雌酚样的抗骨质疏松效果。 ORCID: 0000-0002-9167-5286(赖丽金) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

雌激素干预骨质疏松大鼠牙槽骨改建过程中白细胞介素1的表达

背景：目前大鼠是骨质疏松研究中使用最多的模型动物,其中大鼠去卵巢动物模型应用最广泛,雌性大鼠在卵巢切除后,其骨质变化和给予雌激素后的反应与人相似。 目的：建立骨质疏松拔牙创愈合的大鼠动物模型,研究雌激素应用对骨质疏松大鼠牙槽骨中白细胞介素1分布及表达的影响。 方法：选用65只纯种3月龄雌性大鼠,按随机数字表法分为2组,骨质疏松模型组40只大鼠在全麻下摘除双侧卵巢,25只假手术组摘除卵巢周围与之大小相同的脂肪组织,常规饲养8周以建立大鼠骨质疏松模型。造模成功后全麻拔除大鼠左侧上颌磨牙,病理彩色图像分析仪分析颌骨变化。在骨质疏松模型组中随机抽取15只皮下注射苯甲酸雌二醇作为雌激素治疗组。免疫组织化学法观察白细胞介素1在各组大鼠拔牙后牙槽骨改建过程中的表达变化。 结果与结论：卵巢切除后,骨质疏松模型组大鼠的骨小梁薄而少,骨小梁间距变宽,颌骨骨强度下降。应用雌激素治疗后,发现雌激素治疗组白细胞介素1的阳性表达较骨质疏松组减少。提示3月龄SD雌性大鼠去卵巢8周后可发生骨质疏松,雌激素治疗对骨质疏松大鼠拔牙创骨愈合牙槽骨中白细胞介素1表达有明显的抑制作用。     

毛蕊异黄酮防治去卵巢大鼠骨质疏松的实验研究

目的复制去卵巢大鼠骨质疏松动物模型,观察不同剂量的毛蕊异黄酮对去卵巢大鼠骨质疏松的防治作用。方法 50只SD雌性大鼠,随机分成五组：设一假手术组;腹腔手术切除大鼠双侧卵巢,分为阴性对照组、毛蕊异黄酮低、高剂量组和雌激素对照组,分别给予标准饲料和不同剂量受试物,12周后进行骨密度、骨组织形态计量、生物力学测定,与雌激素对照,观察给与毛蕊异黄酮对绝经后骨质疏松的防治作用。结果大鼠去卵巢后骨密度显著下降,股骨的力学性能有较大变化,弯曲强度和弯曲弹性模量明显降低。给予毛蕊异黄酮后,可使骨密度显著提高（P〈0.01）,存在一定的剂量-效应关系,同时弯曲强度和弯曲弹性模量明显增加,但均低于雌激素对照组。结论通过去卵巢手术,成功建立绝经后骨质疏松动物模型;毛蕊异黄酮对去卵巢大鼠具有显著的骨保护效应,并存在一定的剂量效应关系,其作用弱于雌激素。     

金雀异黄酮对去卵巢大鼠骨质疏松性骨折愈合的实验研究

目的研究金雀异黄酮对去势大鼠发生骨质疏松性骨折愈合的影响。方法成年SD大鼠卵巢摘除后3个月开始制作左侧股骨中段闭合骨折内固定手术模型,并分为骨折组和骨折用药组,每组各20只骨折用药组注射金雀异黄酮,分别于大鼠折骨后15和30dX射线摄片、检测血清骨碱性磷酸酶(B鄄ALP)、I型前胶原羧基端肽(PICP)、骨钙素(BGP)等骨形成生化指标,并与骨折组比较。结果骨折用药组骨痂形成量多,骨折线模糊或消失,B鄄ALP、PICP和BGP水平显著下降(P<0.01)。结论金雀异黄酮可调节骨代谢,促进骨形成,加快大鼠骨折愈合的作用。     

白藜芦醇对去卵巢大鼠骨质疏松症的保护作用

Objective To investigate the protective effect and its mechanism of resveratrol (RES) on rats with osteoporosis. Methods A total of 72 clean grade female SD rats were randomly divided into six cohorts: control cohort, osteoporosis model cohort, estrogen pretreated cohort, low, median and high dosage RES pretreated cohorts. Except for rats in the control cohort, rats in other cohorts were treated by bilateral oophorectomy and pretreated with 17β-E2 and different dosage of resveratrol respectively, ranging from 1 to 12 weeks after operation. The blood parameters associating with osteoporosis were tested. Morphological observation of bone tissue was performed by HE staining under a microscope. Bone mineral density was measured by a dual-energy X-ray absorptiometry. The mRNA expression level of antioxidant enzymes (gpx1, trx1 and γ-gt) were assayed by RT-PCR. Results Serum calcium, serum phosphate, ALP and TRAP increased obviously, but estrogen and calcium level in serum decreased sharply in the animal model. The bone tissue of the model manifested typical osteoporosis characteristics, and the expression of antioxidant enzymes was at a low level. After treated with estrogen or different dosages of resveratrol, the parameters and phenotypes mentioned above were almost close to the control cohort.Conclusion Resveratrol, likely estrogen, can maintain a balance of bone formation and absorbance, which is critical to the homeostasis of bone, antagonizing the osteoporosis pathology progression. This protective mechanism is associated with the expression and activity of antioxidant     

胡椒碱对牙周炎模型牙槽骨和胶原的保护

BACKGROUND: Piperine in models of pancreatitis, gout, middle cerebral artery infarction has anti-inflammatory, antioxidant and immune regulatory effects, but its effects on periodontitis model are not clear.     

Effect of locally administered novel biodegradable chitosan based risedronate/zinc-hydroxyapatite intra-pocket dental film on alveolar bone density in rat model of periodontitis

The aim of this study was to develop a chitosan-based risedronate/zinc-hydroxyapatite intrapocket dental film (CRZHDF) for applications in the treatment of alveolar bone loss in an animal model of periodontitis. The physical characteristics (folding endurance, pH, mucoadhesive strength, risedronate content and release) of CRZHDF, exhibited results within the limit. X-ray diffraction analysis indicates reduced or disappeared crystallinity of risedronate and zinc-hydroxyapatite in presence of chitosan. Further, FTIR studies revealed stability of CRZHDF and compatibility between risedronate, zinc-hydroxyapatite and chitosan. Periodontitis was induced by Porphyromonas gingivalis-lipopolysaccharide injections around the mandibular first molar. We divided rats into 5 groups (12 rats/group): healthy, untreated periodontitis; periodontitis plus CRZHDF-A, periodontitis plus CRZHDF-B, and periodontitis plus chitosan film. After four weeks, blood samples and mandibles were obtained for biochemical, radiographic and histological analysis. Bone specific alkaline phosphatise activity and tartrate resistant acid phosphatase 5b was statistically lower in CRZHDF-A and CRZHDF-B groups as compared to the untreated periodontitis group (p < 0.0001). The expression of osteocalcin was statistically higher in CRZHDF-A and CRZHDF-B groups as compared to the untreated periodontitis group (p < 0.0001). Alveolar bone was intact in the healthy group. Local administration of CRZHDF resulted in significant improvements in the mesial and distal periodontal bone support (MPBS and DPBS, respectively) proportions (%), bone mineral density, and also reversed alveolar bone resorption when compared to the untreated periodontitis group (p < 0.001). The study reported here reveals that novel CRZHDF treatment effectively reduced alveolar bone destruction and contributes to periodontal healing in a rat model of experimental periodontitis.     

Fusobacterium nucleatum and Tannerella forsythia induce synergistic alveolar bone loss in a mouse periodontitis model

Tannerella forsythia is strongly associated with chronic periodontitis, an inflammatory disease of the tooth-supporting tissues, leading to tooth loss. Fusobacterium nucleatum, an opportunistic pathogen, is thought to promote dental plaque formation by serving as a bridge bacterium between early- and late-colonizing species of the oral cavity. Previous studies have shown that F. nucleatum species synergize with T. forsythia during biofilm formation and pathogenesis. In the present study, we showed that coinfection of F. nucleatum and T. forsythia is more potent than infection with either species alone in inducing NF-κB activity and proinflammatory cytokine secretion in monocytic cells and primary murine macrophages. Moreover, in a murine model of periodontitis, mixed infection with the two species induces synergistic alveolar bone loss, characterized by bone loss which is greater than the additive alveolar bone losses induced by each species alone. Further, in comparison to the single-species infection, mixed infection caused significantly increased inflammatory cell infiltration in the gingivae and osteoclastic activity in the jaw bones. These data show that F. nucleatum subspecies and T. forsythia synergistically stimulate the host immune response and induce alveolar bone loss in a murine experimental periodontitis model.     

补骨脂提取物干预骨质疏松模型大鼠骨密度及骨生物力学的变化

文题释义： RANKL/OPG通路：核因子κB受体活化因子配体(receptor activator of NF-κB Ligand,RANKL)/骨保护蛋白在维持成骨与破骨的动态平衡,调节骨代谢功能方面发挥着重要作用。RANKL 可与破骨细胞前体细胞膜表面的核因子κB受体活化因子结合,促进破骨细胞分化和激活,抑制其凋亡,最终促进骨吸收;骨保护蛋白作为RANKL的天然抗体,可与RANKL直接结合,竞争性抑制核因子κB受体活化因子与其的结合,进而抑制破骨细胞分化、成熟,最终抑制骨吸收。生理状态下,体内RANKL与骨保护蛋白的表达保持一定的比例,若二者表达比例失衡,则会造成骨代谢紊乱,导致骨相关疾病发生。 骨生物力学：是骨组织在外力作用下的力学生物学效应,对其进行检测可直接评价骨质量,是评价各种治疗骨丢失措施的最佳方案,其检测指标包括弹性模量、最大载荷、屈服载荷等。 背景：地塞米松作为一种糖皮质激素,长期应用会破坏成骨与破骨的动态平衡,降低骨密度,损伤骨生物力学,调控核因子κB受体活化因子配体(receptor activator of NF-κB ligand,RANKL)/骨保护蛋白通路可能影响地塞米松诱导的骨质疏松症大鼠骨密度及骨生物力学。 目的：探讨基于RANKL/骨保护蛋白通路研究补骨脂提取物对地塞米松诱导骨质疏松症大鼠骨密度及骨生物力学的影响。 方法：SPF级Wistar大鼠肌肉注射地塞米松,建立骨质疏松大鼠模型。选择1×10⁷ TU/mL浓度的慢病毒载体进行实验。将模型大鼠随机分为模型组、空载组(空慢病毒载体)、骨保护蛋白沉默组(含骨保护蛋白基因干扰片段的慢病毒载体)、补骨脂提取物组、补骨脂提取物+骨保护蛋白沉默组,每组12只,另取12只正常大鼠设为对照组。药物处理后,采用骨密度仪测定大鼠左侧股骨骨密度,采用力学实验测试机测定大鼠右侧股骨生物力学指标弹性模量、最大载荷、屈服载荷,测定大鼠股骨骨矿物盐含量,酶联免疫吸附法检测血清中RANKL、骨保护蛋白水平,蛋白免疫印迹法检测骨组织中RANKL、骨保护蛋白表达水平。实验方案经青海大学医学院动物实验伦理委员会批准(批准号为2017081501) 结果与结论：①大鼠骨密度、弹性模量、最大载荷、屈服载荷、骨矿物盐含量、血清中骨保护蛋白水平、骨组织中骨保护蛋白表达：模型组较对照组降低,骨保护蛋白沉默组较模型组降低,补骨脂提取物组较模型组升高,补骨脂提取物+骨保护蛋白沉默组较骨保护蛋白沉默组升高,较补骨脂提取物组降低(均P < 0.05);②大鼠血清中RANKL水平、骨组织中RANKL蛋白表达结果显示,模型组较对照组升高;骨保护蛋白沉默组较模型组升高,补骨脂提取物组较模型组降低,补骨脂提取物+骨保护蛋白沉默组较骨保护蛋白沉默组降低,较补骨脂提取物组升高(均P < 0.05);③模型组与空载组两组间各指标比较无明显变化(P > 0.05);④结果说明,补骨脂提取物可提高地塞米松诱导骨质疏松症大鼠的骨密度,改善其骨生物力学,可能是通过上调骨保护蛋白表达,下调RANKL表达实现的。 ORCID: 0000-0001-9896-6214(周倚墨) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

辛伐他汀对去卵巢大鼠骨痂骨保护素表达的影响

目的: 研究去卵巢及辛伐他汀(simvastatin, SVS)对大鼠骨痂骨保护素(osteoprotegerin, OPG)表达的影响。方法: 2月龄雌性SD大鼠采用去卵巢(ovariectomy, OVX)方法模拟人绝经后骨质疏松症,造模成功后进一步建立胫骨骨折髓内钉内固定模型。大鼠分为3组:假手术组(sham+vehicle)、空白组(OVX+vehicle)及实验组(OVX+SVS)。OVX+SVS组于骨折端皮下注射辛伐他汀(10 mg·kg^-1·d^-1×5 d),sham+vehicle及OVX+vehicle组仅注射无辛伐他汀的空白溶剂。骨折后1、2、4周取骨痂标本,切片免疫组化染色,分析骨痂中的增殖细胞核抗原(PCNA)、OPG表达情况。结果: 结果显示OVX+vehicle组骨折后1、2、4周PCNA阳性率较sham+vehicle组分别下降17.3%、32.1%和26.1%(P<0.01);OVX+SVS组骨折后1、2、4周PCNA阳性率较OVX+vehicle组分别增加60.1%、67.7%和67.7%(P<0.01);半定量结果显示OVX+vehicle组OPG表达水平最低,sham+vehicle组最高,而OVX+SVS组的OPG表达水平介于2组之间,OVX+SVS组与OVX+vehicle组间差异显著(P<0.01)。结论: 本实验显示去势可明显减少骨痂OPG的表达,而辛伐他汀可刺激骨痂分泌OPG,提示他汀类药物具有间接抑制破骨细胞的作用。     

Effects of tooth function on adjacent alveolar bone and Sharpey's fibers of the rat periodontium

There is little information about the effects of short-term non-hypo-, and hyperfunction of teeth on the 1) mineralization patterns of intrinsic and extrinsic (Sharpey's) fibers and 2) mean number and diameter of Sharpey's fibers of adjacent alveolar bone. The mineral density of intrinsic and Sharpey's fibers and the size and number of Sharpey's fibers could indicate the relative strength of the attachment of a tooth to bone in various functional situations. In the present study, non- and hypofunctional situations were created by selective extraction of right molar teeth of the rat; the contralateral teeth were placed in hyperfunction by the surgery. In non- and hypofunctionals, intrinsic and Sharpey's fibers of the crestal third of the alveolus were less densely mineralized than in hyperfunctionals or untreated controls. Mean Sharpey's fiber diameters were significantly greater and their mean number/unit area significantly less in non- than in hypo- or hyperfunctionals or untreated controls (P less than 0.001). Mean Sharpey's fiber diameters in hyperfunctionals were significantly less than in untreated controls (P less than 0.05). Hypofunction ameliorated the effects of nonfunction on mean diameter and number of Sharpey's fibers, but had little effect on the density of mineralization of either the intrinsic or Sharpey's fibers of the alveolus, suggesting that their mineralization may be controlled by factors other than occlusal forces from the adjacent teeth. Thus changes in the stress/strain environment within the periodontium, coincident to altered occlusal function of the adjacent teeth, rapidly affects the morphology of intrinsic and Sharpey's fibers of alveolar bone and ensures that adequate tooth support is maintained in the new functional situation.     

Effect of X-ray irradiation on primary mineralization in rat alveolar bone

Summary The effect of X-ray irradiation on the process of primary mineralization in bone was studied by biochemical and ultrastructural methods. A single dose of 1500R was administered to the head region of rats. The animals were examined immediately after irradiation and 1, 2 and 3 weeks later. Fractions of isolated cells and extracellular matrix vesicles were prepared from the maxillary alveolar bone of irradiated and untreated rats by collagenase digestion and differential centrifugation. The protein content and activities of vesicular phosphatases were determined in both fractions. A continuous decrease in the activity of alkaline phosphatase could be observed in both cell and matrix vesicle fractions during a three-week follow up after irradiation. Acid phosphatase activity decreased only in the vesicle fraction.Transmission electron microscopy of irradiated bone tissue revealed that many matrix vesicles were devoid of intact membranes and apatite crystals. Calcifying nodules were abundant in the matrix without their apparent fusion into larger mineralized structures. It is suggested that irradiation interferes with enzymatic processes associated with primary mineralization.     

Dynamic histomorphometry of alveolar bone remodeling in the adult rat

Alveolar bone normally undergoes remodeling on one side of the socket and modeling on the opposite side as the tooth migrates at a rate of 6.7 μm per day. Periodontal ligament width, however, remains constant. Because of this very high turnover rate, this bone is a good model to study bone modeling and remodeling activities. This study was undertaken in order to measure the different cellular events occurring during tooth migration along the alveolar bone of the rat. The histomorphometric measurements performed on this model permitted us to calculate the duration of each phase of the remodeling cycle, i.e., resorption lasts about 1.5 days and reversal about 3.5 days. Since the duration of the forming phase is about 1 day (Guyomard and Baron, ′74), the total duration of each remodeling cycle is about 6 days. This time is very short compared to 60–120 days in adult human trabecular bone. Additionally, in this model each osteoclast resorbs 2–4 times its own volume of bone per day. Based on this knowledge, it will be possible to measure accurately the effects of experimental conditions on bone cells and bone remodeling in this rat alveolar bone model.     

培哚普利对维甲酸所致骨质疏松模型大鼠骨代谢的影响

BACKGROUND: Renin-angiotensin-aldosterone system existed in bone tissue. Recent studies on antihypertensive drugs found that angiotensin converting enzyme inhibitor type antihypertensive drug was possibly effective for osteoporosis. Perindopril is one of the commonly used antihypertensive drugs. Whether perindopril affected bone metabolism or could be used in anti-osteoporosis has not been reported.