代谢性谷氨酸受体第5亚型论文：代谢性谷氨酸受体第5亚型(mGluR5)在正常和炎症牙髓中的表达及分布.doc

代谢性谷氨酸受体第5亚型论文：代谢性谷氨酸受体第5亚型（mGluR5）在正常和炎症牙髓中的表达及分布【中文摘要】代谢性谷氨酸受体第5亚型(mGluR5)是一组新型的G蛋白偶联受体,存在于哺乳动物的脑和脊髓中,通过兴奋性神经中枢参与炎症和神经病理性疼痛的传递过程,mGluR5受体的活化会增强疼痛的状态。mGluR5受体选择性拮抗剂(MPEP)有镇痛作用。牙髓分布着密集的感觉神经,一旦受到刺激就会传递疼痛信号发生疼痛,这些神经来自脑内的三叉神经。近年来有实验研究表明在正常牙髓冠髓的成牙本质细胞中分布有mGluR5,但在炎症牙髓或正常牙髓的其他部位mGluR5的表达及分布情况尚不明确,本实验利用免疫组化的方法检测了正常牙髓各部位和炎症牙髓冠髓mGluR5的表达及分布情况；利用图像分析系统,对其表达强度进行了半定量分析,探讨了mGluR5在正常牙髓和炎症牙髓中的作用和意义,为临床上牙髓炎的靶向治疗提供一种新的思路。方法：1.收集山东大学口腔医院口腔颌面外科的患者因正畸或其他治疗需要而拔除的健康前磨牙或第三磨牙5例,作为牙髓健康组；临床及病理确诊的急性牙髓炎和慢性牙髓炎组各5例,将每个标本进行连续组织切片,作HE染色和免疫组化染色,以磷酸盐缓冲液(phosphatic buffer solution, PBS)代替一抗作阴性对照。2.对免疫组化的结果进行图像分析：利用IPP5.0图像分析系统,自切片染色中心区域上下左右各选择相同面积有代表性的区域,检测平均光密度(mean optical density, MOD),对表达强度进行半定量分析。3.采用SPSS软件对实验结果进行统计学处理：mGluR5表达的光密度值以均数标准差(XS)表示。显著性检验采用单因素方差分析,组间比较采用LSD检验。P0.05有统计学意义。结果：1.肉眼观察结果：健康牙髓红润有光泽,体积较大,组织柔韧性好,容易从硬组织上剥脱。炎症牙髓体积较小,脆性大、易断裂。2.HE染色结果：正常牙髓冠髓成牙本质细胞呈高柱状,在颈部和根中部呈立方状,而在根尖区呈扁平状；慢性牙髓炎成牙本质细胞排列不规则,细胞层的连续性被破坏,牙髓组织中有大量的慢性炎细胞浸润,主要为淋巴细胞和浆细胞；急性牙髓炎龋损下方成牙本质细胞的连续性被破坏,牙髓血管扩张充血,血管通透性增加,液体渗出,组织水肿,沿血管壁周围有中性粒细胞浸润。3.免疫组化结果：正常牙髓冠部、颈部到根部牙髓及炎症牙髓的冠髓成牙本质细胞中mGluR5的表达呈现阳性,其分布情况为：正常牙髓由冠部、颈部到根部mGluR5表达强度依次降低；急性牙髓炎、慢性牙髓炎及正常牙髓的冠髓mGluR5表达强度依次降低。4.mGluR5免疫组化结果的平均光密度检测：按=0.05的检验水准,正常牙髓冠部、颈部和根部mGluR5平均光密度值有统计学意义(P0.05),LSD法组间两两比较P值均小于0.001,表明正常牙髓由冠部、颈部到根部mGluR5表达量依次降低；急性牙髓炎、慢性牙髓炎和正常牙髓冠髓的mGluR5平均光密度值有统计学意义(P0.05),LSD法组间两两比较P值均小于0.001,表明急性牙髓炎、慢性牙髓炎及正常牙髓的冠髓mGluR5表达量依次降低。结论：1.正常牙髓和炎症牙髓的成牙本质细胞中存在mG1uR5的表达。2.正常牙髓由冠部、颈部到根部mGluR5表达强度依次降低；急性牙髓炎、慢性牙髓炎及正常牙髓的冠髓mGluR5表达强度依次降低。3.提示mGluR5在牙髓疼痛的传递过程中具有一定的作用。推断应用mGluR5受体选择性拮抗剂(如MPEP)可阻断牙髓疼痛的传递,为临床上牙髓炎的靶向治疗提供了一种新的思路。【英文摘要】:mGluR5 mediates modulatory responses by coupling to guanine nucleotide-binding proteins. Besides its action in the brain, glutamate plays a key role in excitatory neurotransmission in the mammalian spinal cord and may be involved in pathological conditions of the spinal cord via excitotoxicity. It has previously been shown to play a role in pain transmission during inflammatory or neuropathic pain states. mGluR5 receptor is activated to enhance pain states, so selective mGluR5 antagonist,2-methyl-6-(phenylethynyl)pyridine (MPEP)is used to ease pain. The tooth pulp has a dense sensory innervation which, upon stimulation, conveys sensory signals perceived as pain. This innervation originates from the trigeminal ganglion. For the past few years, an experiment shows mGluR5 is expressed in human normal coronal pulp, however no define datas show mGluR5 is exsited in human inflammatory pulp or normal pulp else. This experiment checks the expression and distribution mGluR5 in human inflammatory pulp or normal pulp else by immunohistochemistry. We observe and explore the change and the role states of mGluR5, thus this will supply a new train of thought to cure pulp disease.Methods:1. Human premolars and third molars (n=5) that were extracted for orthodontic or treatment needs from patients at the Department of Oral Surgery, Shan Dong University Oral Hospital, were collected. Acute pulpitis (n=5)and chronic pulpitis(n=5)were defined clinically and pathologically. Serial tissue sections were cut for HE staining, immunohistochemical staining and PBS negative control respectively.2. The results of immunohistochemestry analysis:Digital image processing was used to analyse the expression of mGluR5. The optical density(OD)of the normal and inflammatory pulps were obtained by means of semi-quantitation in five random highpower fields of each section.3. SPSS software statistical treatment:Data was analyzed by ANOVA and LSD methods, and expressed as the meansSD. Value of P0.05 was considered statistically significant.Results:1. The results of naked eyes observing:Healthy pulps are colorful and sheen. The healthy pulps are solid and flexible. The pulps are easily exfoliated from sclerous tissues. While the solidity of inflammatory pulps are small and brittleness to part.2. HE stanining results:The odontoblasts in normal cornal pulps are longitudinal, in the cervical and mid-coronal regions of the pulp are cubical, while in the root of the pulps are flat. The odontoblast layer is destroyed and the major chronic inflammation cells are lymphocytes in the chronic pulpitis tissues. The odontoblast layer is destroyed seriously and neutrophils are infiltrated around blood vessels in acute pulpitis tissues. The blood vessels in pulpitis tissues expand resulted in increasing permeability, so fluid exudation and tissue edema appear.3. Results of Immunohistochemistry:The expression of mGluR5 is positive in the whole normal pulp and the cornal of inflammatory pulp, while the expression of mGluR5 shows significantly weaker from cornal, cervical portion to root of normal pulp in turns, the expression of mGluR5 shows a significantly weaker from cornal of normal pulp, acute pulpitis to chropic pulpitis in turns.4. Analysis of the values of ODs in Immunohistochemistry:mGluR5 shows a significantly(P0.05) weaker expression from cornal, cervical portion to root of normal pulp in turns. mGluR5 shows a significantly (P0.05) weaker expression from cornal of normal pulp, acute pulpitis to chropic pulpitis in turns.Conelusions:1.mGluR5 shows a significantly weaker expression in turns from cornal, cervical portion to root of normal pulps.2. mGluR5 shows a significantly weaker expression in turns from cornal of acute pulpitis,chropic pulpitis to normal pulps.3.The expression and distribution differences of mGluR5 in normal pulp and pulpitis suggest that it may play an important role in transduction of pulp nociceptive signals. A subtype-selective mGluR5 antagonist (MPEP) can be used to block pain. This will supply a new train of thought to treat