染料木素对牙周炎小鼠牙周组织的影响

目的 本研究旨在评估染料木素（genistein,GEN）对丝线结扎诱导的牙周炎小鼠牙槽骨吸收以及牙龈组织中炎症因子表达情况的影响。方法 以雄性C57小鼠为研究对象,采用丝线结扎法建立小鼠牙周炎模型,实验组给予GEN。4周后使用显微镜和ImageJ软件分析GEN对小鼠牙槽骨吸收情况的影响。并采用实时荧光定量PCR法检测GEN治疗后,牙周炎小鼠牙龈组织中肿瘤坏死因子（tumor necrosis factor-α,TNF-α）、白细胞介素-1β(interleukin-1β,IL-1β)、白细胞介素-6(interleukin-6,IL-6)以及白细胞介素17a(interleukin-17a,IL-17a)的mRNA表达情况。结果 给予GEN(20mg/kg和40mg/kg)治疗后,牙周炎小鼠的牙槽骨吸收明显少于无GEN治疗组（P <0.05）。并且GEN治疗小鼠牙龈组织中TNF-α、IL-1β、IL-6和IL-17a的mRNA表达亦显著降低（P <0.05）。结论 染料木素可显著减轻牙周炎导致的牙周组织破坏,有望成为一种新型的牙周炎治疗药物。     

抗牙龈素粘附片段Hgp44卵黄抗体对实验性牙周炎的抑制作用

目的: 观察抗牙龈素粘附片段Hgp44卵黄抗体(抗Hgp44-IgY)对大鼠实验性牙周炎的抑制作用。方法: 24只雄性SD大鼠随机分为4组:空白组(A),生理盐水孵育组(B),抗Hgp44-IgY孵育组(C)和西吡氯铵孵育组(D)。采用细线结扎大鼠4颗第一磨牙,分别接种经处理的牙龈卟啉单胞菌,辅以蔗糖饮水。4周后检测大鼠牙龈指数(GI),龈下菌斑的BANA试验。处死大鼠后检测牙槽骨丧失量(ABL),牙龈的HE染色,利用qRT-PCR检测牙龈中IL-10、OPG和RANKL mRNA相对表达水平以及OPG/RANKL比率。结果: C组和D组与B组相比,GI、ABL以及BANA结果均显著降低(P<0.01),牙龈组织中IL-10和OPG的mRNA表达水平均显著增高(P<0.01),RANKL mRNA的表达水平显著下降(P<0.05),OPG/RANKL比率显著增高(P<0.001),C组与D组相比,GI、ABL、BANA、IL-10,OPG mRNA水平和OPG/RANKL比率无统计学意义,OPG mRNA 表达水平显著降低(P<0.05)。结论: 抗Hgp44-IgY能减少牙槽骨的吸收,减缓大鼠实验性牙周炎的发展进程。     

IL-10mRNA及其蛋白在慢性牙周炎牙龈组织中的表达

目的检测IL-10 mRNA及其蛋白在慢性牙周炎牙龈组织中的表达及其组织细胞来源.方法随机选择12例慢性牙周炎翻瓣术患者作为牙周炎组,10例龈切术患者作为牙龈炎组,6例阻生牙拔除术患者作为健康对照组.分别采用原位杂交和免疫组化检测技术,检测各组牙龈标本中IL-10的表达.每组IL-10 mRNA及蛋白两种水平间的比较采用秩和检验;各组间数据的两两比较采用单因素方差分析.结果IL-10 mRNA及其蛋白在牙周局部牙龈组织均有表达,表达细胞类型有淋巴细胞、浆细胞、巨噬细胞及成纤维细胞等.IL-10在mRNA水平及蛋白水平表达无显著差异(P＞0.05)(牙龈炎组P＜0.05).牙周炎组IL-10表达强度显著高于健康对照组和牙龈炎组(P＜0.01),牙周炎组IL-10 mRNA表达强度显著高于健康对照组(P＜0.01),但与牙龈炎组比较差异无显著性(P＞0.05).结论IL-10在牙周组织中存在局部分泌机制.     

TNF-α、sICAM-1在慢性间歇低氧条件下大鼠牙周炎发病机制中的作用

目的：探讨慢性间歇低氧和常氧条件下大鼠血清和牙龈组织中肿瘤坏死因子-α（TNF-α）、可溶性细胞间黏附分子-1（sICAM-1）在牙周炎发病机制中的作用。方法：将32只雄性 SD 大鼠随机分为4组（n ＝8）：常氧对照组（A 组）、常氧牙周炎组（B 组）、低氧对照组（C 组）、低氧牙周炎组（D 组）。采用正畸丝结扎双侧上颌第二磨牙和牙周炎食谱的方法建立牙周炎模型,常氧组和低氧组分别在常氧和模拟阻塞性呼吸暂停低通气综合征条件下饲养8周,检测各组动物牙周组织各项临床指标,用 ELISA 法检测动物血清和牙龈组织中 TNF-α、sICAM-1表达。结果：低氧牙周炎组中 TNF-α、sICAM-1浓度显著高于其余各组 P ＜0．05。血清和牙龈组织中 TNF-α、sICAM-1与附着丧失（AL）成正相关（P ＜0．05）。结论：慢性间歇低氧条件下 TNF-α、sICAM-1在牙周组织中的表达水平升高,加重了牙周炎症破坏程度,同时促使炎症反应向外周血管扩散。     

活性氧/c-Jun氨基末端激酶/核因子-κB信号分子通过调控凋亡参与牙周炎诱导肝损伤

目的 牙周炎和非酒精性脂肪性肝病（NAFLD）的发生发展与活性氧（ROS）的大量积累密切相关。ROS参与调控c-Jun氨基末端激酶（JNK）/核因子-κB（NF-κB）信号分子的激活,当该信号分子被ROS过度激活后可引发机体内环境紊乱。因此,本研究旨在探究ROS/JNK/NF-κB信号分子在牙周炎诱导肝损伤中的作用机制。 方法 将12只SPF级雄性Wistar大鼠随机分为对照组和牙周炎组,在牙周炎组大鼠双侧上颌第一磨牙颈部进行钢丝结扎构建牙周炎模型,8周后检查大鼠牙周临床指标并处死,Micro-CT重建牙槽骨三维结构并分析牙槽骨吸收情况,组织病理学分析牙周及肝组织的病理改变,MitoSOX red试剂检测肝组织中ROS含量,生化试剂盒检测肝功指标和氧化应激生物标志物,实时荧光定量聚合酶链反应（qRT-PCR）检测肝组织中NF-κB、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、BCL2-Associated X的蛋白质（Bax）和B淋巴细胞瘤-2基因（Bcl-2）mRNA表达水平,蛋白免疫印迹（Western blot）法检测肝组织中磷酸化c-Jun氨基末端激酶（P-JNK）、JNK、NF-κB、Bax、Bcl-2和半胱氨酸天冬氨酸蛋白酶3（Caspase-3）蛋白表达水平,末端脱氧核苷酸转移酶dUTP缺口末端标记（TUNEL）染色法检测肝细胞凋亡。 结果 Micro-CT结果显示,牙周炎组大鼠牙槽骨骨质吸收明显,且釉牙骨质界到牙槽嵴顶的距离明显大于对照组。组织病理学结果显示,牙周炎组大鼠牙周组织内可见大量炎症细胞浸润和牙槽骨明显吸收;肝组织结构破坏,可见大量气球样变和红色脂滴形成。MitoSOX red染色结果显示牙周炎组肝组织中ROS含量明显升高。生化检测结果显示,牙周炎组血清中谷草转氨酶（AST）和谷丙转氨酶（ALT）含量升高;肝组织中超氧化物歧化酶（SOD）和谷胱甘肽（GSH）含量降低,丙二醛（MDA）含量升高。qRT-PCR和Western blot结果显示,牙周炎组肝组织中IL-6、TNF-α、Bax和NF-κB mRNA及P-JNK/JNK、NF-κB、Caspase-3和Bax蛋白表达水平较对照组显著上升,而Bcl-2 mRNA和蛋白表达水平下降。TUNEL染色结果显示牙周炎组肝组织中凋亡细胞数量明显增多。 结论 ROS/JNK/ NF-κB信号分子通过调控细胞凋亡参与牙周炎诱导肝损伤。     

联用大黄素、黄芩苷对牙周炎大鼠炎症因子影响的研究

目的观察大黄素、黄芩苷联用对牙周炎大鼠牙龈组织炎症因子的影响。方法采用钢丝结扎配合高糖饮食喂养法建立大鼠牙周炎模型,随机分为空白对照组、模型组、替硝唑治疗组、黄芩苷治疗组、大黄素治疗组、黄芩苷与大黄素联用组。分别于实验第4、8周处死,取牙龈组织匀浆,ELISA法检测TNF-α、IL-6含量。结果大鼠建模后牙周炎症状明显,组织TNF-α、IL-6含量均不同程度升高,其中模型组升高最显著,联用组在4、8周时间点牙龈组织TNF-α和IL-6含量均较大黄素组明显降低(P<0.05),而与黄芩苷组比较,在早期(4周时间点)TNF-α和IL-6含量显著降低(P<0.05),但8周时2组无显著性差异。结论大黄素和黄芩苷联用可明显降低牙周炎大鼠牙龈组织TNF-α和IL-6含量,其疗效优于单用大黄素或黄芩苷。     

黄芩苷对大鼠实验性牙周炎的保护效应及作用机制研究

目的 观察黄芩苷对丝线结扎诱导的大鼠牙周组织炎性破坏的保护作用,并探讨这一作用是否与牙龈组织中基质金属蛋白酶(matrix metalloproteinases,MMP)表达水平的改变有关.方法 将SD大鼠按随机数字表法分为3组,每组9只.用丝线结扎方法建立牙周炎模型,建模第7天处死动物.用药组(B200组)每天灌胃给予黄芩苷200 mg/kg;阴性对照组(L组)每天灌胃药物媒介0.5%羧甲基纤维素钠;空白对照组(C组)不予牙周炎诱导.评价牙槽骨吸收和胶原纤维的面积分数.免疫组化方法检测牙龈组织中MMP-1、MMP-2和MMP-9的表达.结果 B200组的骨吸收值[(0.93±0.04)mm]显著低于L组[(1.03±0.07)mm,P=0.009)];B200组的胶原纤维面积分数[(48.13±18.69)%]显著高于L组[(31.08±14.85)%,P=0.047];与L组相比,应用黄芩苷显著下调了MMP-1(P=0.023)及MMP-9(P=0.042)的水平,并降低了MMP-2的表达(P=0.099).结论 黄芩苷能够减少丝线结扎诱导的大鼠牙周炎的组织破坏,这一作用可能与其抑制MMP-1、MMP-2和MMP-9的表达有关.     

β-防御素基因在牙龈组织中的表达

目的:检测人β-防御素(HBD-1,-2,-3)基因在牙周炎病变和健康牙龈组织中的表达。方法:应用反转录多聚合酶链反应(RT-PCR)技术检测健康牙龈(HC组,11例)、慢性牙周炎(CP组,12例)和侵袭性牙周炎(AgP组,9例)牙龈组织中HBD-1、HBD-2和HBD-3mRNA表达水平。结果:HBD-1,-2,-3在所有牙龈组织样本中均有mRNA表达;HBD-3mRNA在HC组、CP组、AgP组的表达水平分别为0.53±0.12,0.30±0.17和0.40±0.17,3组间差异有统计学意义(P<0.01),健康牙龈中HBD-3mRNA表达相对强度明显高于慢性牙周炎组;HBD-2和HBD-3基因的mRNA表达水平呈正相关(P<0.01,r=0.48)。结论:牙龈上皮表达的β-防御素(HBD-1,-2,-3),尤其是HBD-3在健康牙龈组织较高水平的mRNA表达,提示其在牙周宿主免疫防御反应中可能发挥重要作用。     

晚期糖基化终末产物受体在2型糖尿病伴牙周炎患者牙龈中表达

目的:探讨晚期糖基化终末产物受体(RAGE)在非胰岛素依赖型糖尿病伴发牙周炎患者牙龈组织中的分布及其在牙周组织破坏中的作用。方法:用免疫组化方法检测9名患者共20个位点牙龈组织中RAGE和肿瘤坏死因子α(TNF-α)的分布,并进行了半定量检测。其中慢性牙周炎(CP)患者5名,非胰岛素依赖型糖尿病(NIDDM)伴发牙周炎患者4名。同时,应用酶联免疫吸附测定法(ELISA)对相应位点龈沟液及外周血中的白细胞介素6(IL-6)及TNF-α进行测量。结果:RAGE阳性细胞在2组的龈组织中的差异具有极显著性,且RAGE的表达与TNF-α的表达显著相关(P<0.05)。2组龈沟液中IL-6及TNF-α浓度的差异无显著性,但二者的浓度在NIDDM组有高于CP组的趋势。结论:RAGE参与了NIDDM伴发牙周炎患者的牙周组织的破坏。     

基质金属蛋白酶-2在人慢性牙周炎肥大细胞上表达的研究

目的观察基质金属蛋白酶-2(matrix metalloproteinase-2,MMP-2)在慢性牙周炎牙龈组织中肥大细胞上的表达,探讨MMP-2-tryptase双阳性肥大细胞(mast cells,MCs)在慢性牙周炎发病机制中的作用。方法将45例参试者依据慢性牙周炎的病变程度分成3组:健康对照组15例;轻度牙周炎组15例;重度牙周炎组15例。牙龈标本经10%福尔马林液固定48 h;制作牙龈组织连续切片,HE染色,光学显微镜下观察组织学改变;采用免疫荧光双染色法,荧光显微镜下观察牙龈组织中MMP-2-tryptase双阳性MCs的表达情况。结果与健康对照组相比,轻度和重度慢性牙周炎组牙龈组织MMP-2-tryptase双阳性MCs密度均显著升高(P<0.01);重度慢性牙周炎组牙龈组织MMP-2-tryptase双阳性MCs密度显著高于轻度牙周炎组(P<0.05)。结论慢性牙周炎牙龈组织MMP-2-tryptase双阳性MCs密度与牙周炎病变程度的趋势相一致,MMP-2-tryptase双阳性MCs在牙周炎的进展中可能有促进作用。     

Expression levels of adiponectin receptors and periodontitis

Yamaguchi N, Hamachi T, Kamio N, Akifusa S, Masuda K, Nakamura Y, Nonaka K, Maeda K, Hanazawa S, Yamashita Y. Expression levels of adiponectin receptors and periodontitis. J Periodont Res 2010; 45: 296–300. © 2010 John Wiley & Sons A/S Background and Objective: We recently showed that adiponectin, an adipocyte‐derived cytokine, may function as a negative regulator of the Toll‐like receptor signaling pathway and of osteoclast formation in periodontal disease. In this study, we investigated whether the expression levels of adiponectin receptors (AdipoR1 and AdipoR2) are related to the presence of periodontitis. Material and Methods: We initially examined, using RT‐PCR, the expression of the AdipoR1 and AdipoR2 genes at the mRNA level in several oral tissues of C57BL mice. Next, we investigated (using real‐time PCR assays) whether inflammatory cytokines, such as tumor necrosis factor‐α, could affect the expression levels of these genes in human gingival fibroblasts. Lastly, we compared the expression levels of these receptor proteins in gingival tissues between two healthy subjects and five patients with severe periodontal disease using western blotting analysis. Results: The AdipoR1 and AdipoR2 receptors were ubiquitously expressed in the oral tissues of mice. We observed that treatment with tumor necrosis factor‐α could significantly reduce the expression levels of both AdipoR1 and AdipoR2 genes in human gingival fibroblasts. Moreover, we found that the expression of both receptors was lower in periodontal tissues from patients with severe periodontitis than in patients with healthy periodontal tissues. Conclusion: These observations suggest that adiponectin may not function efficiently in sites of periodontal disease because of a decrease in the number of its receptors, and this probable dysfunction may play a role in worsening periodontitis in patients.     

环孢素A和肿瘤坏死因子α对人牙龈成纤维细胞增殖的影响

目的 研究环孢素A(cyclosporinA)和肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)对体外培养人牙龈成纤维细胞增殖的影响,探讨牙龈炎症与药物性牙龈增生的关系及环孢素A所致牙龈增生的相关机制.方法用原代培养的方法获取5名健康人的牙龈成纤维细胞,体外培养、传代后取其中1个生长良好的组织块4～8代细胞用于实验.按以下条件进行实验分组:A组:空白对照组;B1组:10 μg/L环孢素A,B2组:50 μg/L环孢素A,B3组:250 μg/L环孢素A,B4组:1250 μg/L环孢素A;C组:5μg/L TNF-α; D1组:10 μg/L环孢素A+5μg/L TNF-α,D2组:50 μg/L 环孢素 A+5μg/L TNF-α,D3组:250 μg/L环孢素A+5μg/L TNF-α,D4组:1250 μg/L环孢素A+ 5 μg/L TNF-α.将条件培养液分别作用于牙龈成纤维细胞,培养3、5、7d后用甲基噻唑基四唑法测定细胞的增殖情况.结果不同质量浓度的环孢素A作用于成纤维细胞后,细胞的增殖受到抑制,A值下降,其中B1、B2、B3组与A组相比差异无统计学意义,B4组与A组相比差异具有统计学意义(P =0.001);5μg/L的TNF-α作用于成纤维细胞可以刺激细胞的增殖,A值(0.542)与A组(0.441)相比显著升高(P＜0.01).环孢素A和TNF-α共同作用于成纤维细胞后,D1、D2、D3组A值均较A组升高,但均较C组显著降低(P＜0.05).D4组细胞增殖显著增加,与C组相比差异具有统计学意义(P＜0.01).结论环孢素A对成纤维细胞的增殖无促进作用,高浓度时可抑制细胞的增殖;TNF-α可以促进成纤维细胞的增殖;高浓度环孢素A与TNF-α共同作用于成纤维细胞可促进成纤维细胞增殖,提示在一定浓度下环孢素A可能放大了TNF-α刺激成纤维细胞增殖的效应.     

MMP-2在吸烟牙周炎患者牙龈组织中的表达

目的:从MMP-2的酶活性和mRNA水平探讨吸烟与牙周病的关系。方法:利用明胶酶活性分析(zymog-raphy)和RT-PCR方法,分别检测6例吸烟牙周病、6例不吸烟牙周病、6例吸烟正常人、6例不吸烟正常人的牙龈组织中MMP-2的酶活性和mRNA表达。结果:吸烟和牙周病牙龈组织中MMP-2酶活性都较正常组有增加,但吸烟牙周病组的MMP-2的酶活性与吸烟无牙周病组和不吸烟牙周病组有明显差异(P<0.01),吸烟牙周病患者牙周组织中MMP-2的mRNA水平较正常组明显增加(P<0.01)。结论:MMP-2在吸烟牙周炎牙周组织的破坏中起重要作用。     

成人牙周炎不同临床状态牙龈组织中白细胞介素-10mRNA的表达

目的探讨白细胞介素-10（IL-10）mRNA在活动期和稳定期牙周炎牙龈组织中的表达状况。方法选择急性牙周脓肿患者12例、牙周炎基础治疗后稳定期患者12例及阻生第三磨牙拔除患者6例为研究对象,分别设为试验A组（活动期组）、试验B组（稳定期组）和对照组,采集牙龈组织样本,采用原位杂交技术检测3组样本中IL-10mRNA的表达,并进行半定量分析。结果IL-10 mRNA表达阳性的细胞类型主要有淋巴细胞、巨噬细胞及牙龈成纤维细胞。试验A组IL-10 mRNA的表达量最低,明显低于对照组和试验B组（P＜0.01）;试验B组IL-10 mRNA的表达量最高,高于对照组和试验A组（P＜0.01）。结论IL-10 mRNA表达量与牙周炎的临床状态密切相关。     

慢性牙周炎患者唾液中miR-146a的表达及其与龈沟炎症、MMP-8/TIMP-1水平的关系

目的： 探讨慢性牙周炎患者唾液中miR-146a的表达及其与龈沟炎症、基质金属蛋白酶8（MMP-8）、基质金属蛋白酶抑制剂1（TIMP-1）水平的关系。方法： 选择2015年3月—2017年1月间收治的慢性牙周炎患者68例作为慢性牙周炎组,同期在本院进行体检的健康志愿者50例作为正常对照组。检测2组研究对象唾液中miR-146a的表达量,龈沟液中炎症因子、MMP-8/TIMP-1的水平及牙周临床症状指标。采用SPSS24.软件中的Pearson检验评估慢性牙周炎患者唾液中miR-146a的表达量与病情严重程度的相关关系。结果： 慢性牙周炎患者唾液中miR-146a的表达量显著高于正常对照组（P<0.05）,龈沟液中炎症因子（IL-1β、IL-6、IL-35、TNF-α）水平、牙周临床症状指标（PD、AL、PLI、BI）以及龈沟液中MMP-8、TIMP-1的水平显著高于正常对照组（P<0.05）。Pearson检验发现,慢性牙周炎患者唾液中miR-146a表达量与龈沟炎症程度、牙周临床症状严重程度及MMP-8/TIMP-1水平呈正相关。结论： 慢性牙周炎患者唾液中miR-146a表达量异常增高,且与龈沟炎症程度、牙周损伤程度一致。     

The effects of selective COX-2 inhibitor/celecoxib and omega-3 fatty acid on matrix metalloproteinases, TIMP-1, and laminin-5gamma2-chain immunolocalization in experimental periodontitis

BACKGROUND: Matrix metalloproteinases (MMPs) play important roles in tissue-destruction mechanisms-associated periodontitis. MMP-8 and -13 are the predominant collagenases that are important in the extracellular matrix degradation in periodontal tissues. MMP-14 is a membrane-type MMP, whereas laminin-5 indicates basal membrane modification and epithelial induction. The purpose of the present study was to evaluate the effects of celecoxib and omega-3 fatty acid administration on the gingival tissue expression of MMP-8, -13, and -14, tissue inhibitor of MMP (TIMP)-1, and laminin (Ln)-5gamma2-chain in rat experimental periodontitis induced by Escherichia coli endotoxin (lipopolysaccharide [LPS]). METHODS: Experimental periodontitis was induced in rats by repeated LPS injection. Fifty-one adult male Sprague-Dawley rats were divided into six study groups: saline control, LPS, LPS + celecoxib, LPS + therapeutic omega-3 (TO3), prophylactic omega-3 + LPS + omega-3 (P+TO3), and LPS + celecoxib + omega-3 fatty acid. Celecoxib and omega-3 fatty acid were given as a single agent or as combination therapy for 14 days. On day 15, all rats were sacrificed, and gingival tissues were analyzed immunohistochemically for the expression of MMP-8, -13, and -14, TIMP-1, and Ln-5gamma2-chain. Alveolar bone loss was evaluated morphometrically under a stereomicroscope. Data were tested statistically by Kruskal-Wallis and Mann-Whitney tests and Spearman correlation analysis. RESULTS: Alveolar bone loss was significantly higher in all study groups compared to the saline control group (all P <0.01). MMP-8 expression was significantly higher in the LPS group than in the saline group (P = 0.001). Very low expression of MMP-8 was found in the celecoxib, P+TO3, and combination groups. TO3 increased TIMP-1 expression significantly compared to the LPS group (P <0.05). Individual celecoxib and P+TO3 administration increased MMP-14 significantly compared to saline control and LPS groups (P <0.05). No significant differences were found among the study groups with regard to Ln-5gamma2-chain and MMP-13 expressions (P >0.05). CONCLUSIONS: Selective cyclooxygenase-2 inhibitor, prophylactic omega-3 fatty acid, and a combination of these two agents can inhibit gingival tissue MMP-8 expression. Moreover, the individual administration of therapeutic omega-3 may increase gingival TIMP-1 expression in contrast to no effect on MMP-8, -13, and -14 expressions in experimental periodontitis. These experimental findings in a rat model of LPS-induced periodontitis need to be verified by clinical human studies.     

Matrix metalloproteinases, tissue inhibitor of matrix metalloproteinase-1, and laminin-5 gamma2 chain immunolocalization in gingival tissue of endotoxin-induced periodontitis in rats: effects of low-dose doxycycline and alendronate

BACKGROUND: Matrix metalloproteinases (MMPs) play important roles in tissue destruction mechanisms of periodontitis. MMP-8 and -13 are the major collagenases that act in extracellular matrix degradation in periodontal tissues. MMP-14 is a membrane-type MMP, and laminin (Ln)-5 is a basal membrane component. The aim of the present study was to evaluate the effects of doxycycline and alendronate on gingival tissue expression of MMP-8, -13, and -14; tissue inhibitors of MMP (TIMP)-1; and Ln-5 gamma2 chain in experimental periodontitis induced by Escherichia coli endotoxin (LPS) in rats. METHODS: Experimental periodontitis was induced by repeated injection of LPS. Forty-four adult male Sprague-Dawley rats were divided into five study groups: saline control, LPS, LPS + doxycycline, LPS + alendronate, and LPS + doxycycline + alendronate. Doxycycline and alendronate were given as a single agent or as combination therapy during the 7 days of the experimental study period. On day 7, the rats were sacrificed, and the gingival tissues were analyzed immunohistochemically for expression of MMP-8, -13, and -14, Ln-5 gamma2 chain, and TIMP-1. Alveolar bone loss was evaluated morphometrically under a stereomicroscope. Data were tested statistically by Kruskal-Wallis and Mann-Whitney tests and Spearman correlation analysis. RESULTS: Alveolar bone loss was significantly higher in the LPS, doxycycline, alendronate, and combination groups than in the saline control group (all P <0.01). MMP-8 expression was significantly higher in the LPS group than in the saline control group (P = 0.001). Individual administration of doxycycline or alendronate significantly decreased the expression of MMP-8 compared to LPS (P = 0.01). Combined drug administration reduced MMP-14 significantly compared to doxycycline (P = 0.004). No significant differences in Ln-5 gamma2 chain expression were found between the study groups (P >0.05). MMP-14 significantly correlated with the Ln-5 gamma2 chain in the LPS + alendronate group (P = 0.04) and with the amount of alveolar bone loss in the LPS + doxycycline + alendronate group (P = 0.03). CONCLUSIONS: Our findings suggest that alendronate and/or doxycycline may inhibit MMP-8 expression significantly; particularly, their combined administration may provide beneficial effects in periodontal treatment. Moreover, individual administration of alendronate and doxycycline results in significant increases in TIMP-1 expression in gingiva. However, these effects of combined low-dose doxycycline and alendronate on MMPs and TIMP should be verified by clinical human trials before these agents are used in dental practice.     

硝酸盐对牙龈局部炎症程度影响的实验研究

目的检测分析牙周组织局部滴注硝酸盐后,一氧化氮（NO）含量变化与局部炎症发生和发展的关系,初步探讨硝酸盐在牙周炎症预防与治疗中的作用。方法建立大鼠实验性牙周炎动物模型,将70只健康SD大鼠随机分为正常对照组（N组）,牙龈炎组（P组）和药物对照组（PP组）,其中牙龈炎组又分为1000uM／L硝酸钾（KNO3）滴注组和非KNO3滴注组,所有动物分别于术后1、4周处死,采用酶法检测实验动物牙龈组织中NO2^-和NO3^-的含量,并用肉眼和组织切片观察牙龈组织中炎症的变化情况。结果正常对照组与牙龈炎组中未滴注1000uM／LKNO3溶液的牙龈组织中NO含量有高度显著性差异（P〈0．01）,在牙龈炎组中,牙龈局部给予KNO3溶液滴注与未给予KNO3溶液滴注的牙龈组织中NO含量无显著性差异（P〉0．01）,药物对照组与正常对照组牙龈组织中NO含量有高度显著性差异（P〈0．01）,药物对照组（PP组）与P组未滴注KNO3溶液的牙龈组织中NO含量有显著性差异（P〈0．01）。结论牙周局部给予硝酸盐滴注后能够增加NO的产生,提高局部NO的浓度,从而改善微循环,增强牙周局部抵抗能力,减轻和预防牙周炎症的发生。