da Silva Leopoldo Penteado Nucci, Issa João Paulo Mardegan, Del Bel Elaine Aparecida
Faculty of Dentistry, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Micron. 2008 Oct;39(7):797-801. doi: 10.1016/j.micron.2008.01.018. Epub 2008 Feb 2.
Irreversible pulpitis has been associated with pain and an increase in the number of pulp inflammatory cells. Based on the action of nitric oxide (NO) elsewhere, NO may possibly participate in the sensory and autonomic innervation of the dental pulp, and may influence local inflammatory responses. The purpose of this study was to analyze normal and inflamed human dental pulp for the presence of NADPH-diaphorase (NADPH-d), as an index of NO system activity. Six non-carious second premolar pulp tissue samples were obtained from young patients who required extractions for orthodontic reasons and six inflamed samples were obtained from symptomatic carious second premolars clinically diagnosed with irreversible pulpitis. Pulp tissue was carefully removed, fixed by immersion in a cold 4% PFA buffered solution for 120 min, rinsed in cold phosphate buffer, and quickly-frozen for cryostat sectioning. Pulp tissue was sectioned perpendicularly to the vertical axis of the tooth at 20 microm and processed for histochemistry. Sections of each specimen were stained with hematoxylin-eosin and other sections were subjected to histochemical NADPH-d detection. Results indicated the presence of NADPH reactivity within the pulps of both normal and carious teeth. In the normal teeth NADPH-d activity was detected in a small number of vascular endothelial cells and fibroblasts. The inflammatory response of the pulp from carious premolars was detected in connective tissue by the presence of an increased number of fibroblasts, angioblasts and collagen fibers. It was possible to determine the extent of odontoblast reactivity since the odontoblast layer was usually absent in these split-peel preparations. There were no obvious signs of stained pulpal nerve fibers. Overall NADPH-d staining was significantly more intense within inflamed pulp tissues compared to normal healthy samples (Mann-Whitney test, p<0.002). These results suggest that NADPH-d may be used as a marker of inflammatory activity in pulpitis and provide the basis for further studies aiming to clarify the possible functions of NO in human dental pulp in pathophysiological situations.
不可逆性牙髓炎与疼痛及牙髓炎症细胞数量增加有关。基于一氧化氮（NO）在其他部位的作用，NO可能参与牙髓的感觉和自主神经支配，并可能影响局部炎症反应。本研究的目的是分析正常和发炎的人牙髓中是否存在NADPH黄递酶（NADPH-d），作为NO系统活性的指标。从因正畸需要拔牙的年轻患者中获取6个非龋性第二前磨牙牙髓组织样本，从临床诊断为不可逆性牙髓炎的有症状龋性第二前磨牙中获取6个发炎样本。小心取出牙髓组织，浸入冷的4%多聚甲醛缓冲溶液中固定120分钟，在冷磷酸盐缓冲液中冲洗，然后快速冷冻以备冰冻切片。牙髓组织垂直于牙齿的垂直轴切成20微米厚的切片，并进行组织化学处理。每个标本的切片用苏木精-伊红染色，其他切片进行组织化学NADPH-d检测。结果表明正常和龋性牙齿的牙髓中均存在NADPH反应性。在正常牙齿中，在少数血管内皮细胞和成纤维细胞中检测到NADPH-d活性。在结缔组织中，通过成纤维细胞、成血管细胞和胶原纤维数量的增加检测到龋性前磨牙牙髓的炎症反应。由于在这些剥离制备物中通常不存在成牙本质细胞层，因此可以确定成牙本质细胞反应的程度。没有明显的牙髓神经纤维染色迹象。与正常健康样本相比，发炎牙髓组织中的总体NADPH-d染色明显更强（曼-惠特尼检验，p<0.002）。这些结果表明，NADPH-d可作为牙髓炎炎症活动的标志物，并为进一步研究旨在阐明NO在病理生理情况下人牙髓中可能的功能提供基础。
