RESUMO
Periodontal disease (PD) is a chronic infection that may have local and systemic rebound. Although a series of inflammatory mediators are involved in PD, the mechanisms involved in chronic craniofacial pain associated with it require elucidation. The aim of this study was to evaluate the immunoreactivity of substance P (SP), neuronal (nNOS) and inducible (iNOS) nitric oxide synthases in gingival samples of patients with severe PD with and without chronic craniofacial pain. Gingival specimens were obtained during routine periodontal surgery while managing 20 patients with both PD and chronic craniofacial pain (CFP Group) and 18 patients with only PD (PD Group). Following surgical removal, the tissue underwent routine histological techniques and was stained by immunohistochemistry with antibodies against SP, nNOS and iNOS. Using an image analysis system, we assessed the SP, nNOS and iNOS content in total gingival tissue as well as in both epithelial and connective gingival area. We observed high expression of nNOS in gingival tissue obtained from CFP patients (p<0.001), particularly in the epithelium area (p<0.001) comparatively to PD patients. In addition, the iNOS expression was also increased in the CFP group in the connective gingival tissue (p=0.003). There was no difference concerning SP expression between the groups. Our results suggest that nitric oxide, particularly derived from nNOS, modulates not only PD but also chronic craniofacial pain, since patients with this association presented an increase in nNOS and iNOS expression in gingival tissue.
La enfermedad periodontal (EP) es una patología crónica que pueden tener acción local y sistémica. A pesar de que hay una serie de mediadores inflamatorios implicados en la EP, los mecanismos implicados en el dolor craneofacial crónico asociado con la EP aún no están elucidados. El objetivo fue evaluar la inmunoreactividad de la sustancia P (SP), óxido nítrico sintetasas neuronal (nNOS) e inducible (iNOS) en muestras gingivales de pacientes con enfermedad periodontal severa con y sin dolor craneofacial crónico. Fueron obtenidas muestras gingivales durante la cirugía periodontal rutinaria de 20 pacientes que presentaron con EP y dolor craneofacial crónico (Grupo PPC) y 18 pacientes sólo con PD (Grupo PD). Después de la extirpación quirúrgica, el tejido se sometió a las técnicas histológicas de rutina y se tiñó por inmunohistoquímica con anticuerpos contra el SP, nNOS e iNOS. Se evaluaron el contenido de SP, nNOS e iNOS en el tejido gingival total, así como la superficie gingival, epitelio y tejido conectivo mediante análisis de imagen. Se observó alta expresión de nNOS en el tejido gingival obtenido a partir de pacientes PPC (p<0,001) en comparación a los pacientes con EP, particularmente en el área de epitelio (p<0,001). Además, la expresión de iNOS se incrementó en el tejido conjuntivo gingival (p= 0,003) del grupo PPC. No hubo diferencia en la expresión de SP entre los grupos. Nuestros resultados sugieren que el óxido nítrico, en particular derivado de nNOS, modula no sólo PD, sino también el dolor craneofacial crónico, ya que los pacientes con esta asociación presentan un aumento de la expresión de nNOS e iNOS en el tejido gingival.
RESUMO
INTRODUCTION: Smoking is a serious worldwide public health problem. Animal models act as a bridge between laboratory and human studies. The models applied are difficult to reproduce because of the use of different types of inhalation chambers and mainly because of the lack of continuous monitoring of smoke concentration. OBJECTIVE: To develop an inhalation chamber for rats (with only the nose exposed) in which the amount of carbon monoxide (CO) can be maintained and monitored constantly. MATERIAL AND METHODS: Male Wistar rats weighing 250g were exposed to 50ppm CO produced by the smoke from a filter-free cigarette. The animals were submitted to a single 2-h exposure and then sacrificed at 0, 4, 24 and 48h. The control group was left restrained inside the small perpendicular chambers, receiving only 5L/min of compressed air. RESULTS: The model was able to increase HbCO levels immediately after the end of exposure (p<0.001), with a decrease being observed from 2h onwards when compared to the levels of the control group. Plasma cotinine increased immediately after exposure, and showed still detectable levels at 2 and 4h (p<0.05). CONCLUSION: We conclude that the presented inhalation chamber system is able to maintain a controlled CO concentration in a model in which small animals are exposed to the inhalation of cigarette smoke, permitting well-controlled studies, as well as investigations involving other toxic gases and air pollutants.