ABSTRACT
BACKGROUND AND OBJECTIVES: An experimental model of bacterial rhinosinusitis is essential to study the pathogenesis of rhinosinusitis. To our knowledge, there hasn't been an experimental model using rats for bacterial rhinosinusitis, where Staphylococcus aureus is directly inoculated to the rat nose. Staphylococcus aureus is also a predominantly isolated bacterial pathogen in the episode of acute rhinosinusitis. The aim of this study was to develop a rat model of rhinosinusitis induced by Staphylococcus aureus, ATCC 25923. SUBJECTS AND METHOD: The infected Sprague-Dawley rats (4-6 week-old male) were applied intranasally with 40 microliter of Staphylococcus aureus, ATCC 25923, which corresponds to 108 colony-forming units per milliliter, which in turn corresponds to a No. 1 McFarland turbidity by spectrophotometer (VITEK, USA). After the 2nd, 5th, and 14th day, the rats were killed respectively. RESULTS: Nasal sinuses were then observed at low power field (x40) for changes in the amount of inflammatory cell clusters in the sinus cavity. There were significant differences in the number of inflammatory cell clusters between the infected and control rats (p<0.05). The infected rats killed at the 5th day had significantly more inflammatory cell clusters within the sinus cavities (p<0.05). CONCLUSION: Staphylococcus aureus induces acute bacterial rhinosinusitis in rats as measured by increased inflammatory cell clusters. This study demonstrates the efficacy of a rat model of acute bacterial rhinosinusitis.
Subject(s)
Animals , Rats , Models, Animal , Models, Theoretical , Nose , Paranasal Sinuses , Rats, Sprague-Dawley , Staphylococcus aureus , Staphylococcus , Stem CellsABSTRACT
BACKGROUND AND OBJECTIVE: Platelet-activating factor (PAF), a potent chemical mediator in inflammation and allergic reaction, induces microvascular leakage in several tissues. In rat airways, PAF-induced microvascular leakage is not dependent on cyclooxygenase or lipoxygenase products nor on circulating platelets, and it is probably mediated by receptors on vascular endothelium. Nitric oxide (NO), first identified as endothelium-derived relaxing factor, has been reported recently to be an important mediator of the neurogenic vascular exudative process. The aim of this study was to investigate the role of NO in PAF-induced microvascular leakage in rat nasal and tracheal mucosa. METHODS: PAF (1 ug/kg) was injected intravenously to induce microvascular leakage. The degree of microvascular leakage was measured with the amount of extravasated Evans blue (30 mg/kg) using both spectrophotometry and fluorescence microscopy. Five Sprague-Dawley rats were pretreated with Nw-nitro-L -arginine methyl ester (L-NAME, 10 mg/kg, intravenously, 1 hour before the injection of PAF) to inhibit the NO synthase, while four control rats(n=4) were pretreated with normal saline. RESULT: The average amounts of extravasated Evans blue in the nasal mucosa and trachea of the control rats were 24.789 and 28.238 ug/mg wet tissue, and those of the L-NAME pretreated rats were 6.643 and 6.987 ug/mg wet tissue respectively. Tissue sections of the L-NAME pretreated rats showed a definitely decreased extravasation of Evans blue under fluorescence microscopy. CONCLUSION: Pretreatment with L-NAME clearly inhibited PAF-induced microvascular leakage in the nasal and tracheal mucosa of rat. This finding implies that NO may mediate PAF-induced microvascular leakage in rat airways.
Subject(s)
Animals , Rats , Blood Platelets , Endothelium, Vascular , Endothelium-Dependent Relaxing Factors , Evans Blue , Hypersensitivity , Inflammation , Lipoxygenase , Microscopy, Fluorescence , Mucous Membrane , Nasal Mucosa , NG-Nitroarginine Methyl Ester , Nitric Oxide Synthase , Nitric Oxide , Platelet Activating Factor , Prostaglandin-Endoperoxide Synthases , Rats, Sprague-Dawley , Spectrophotometry , TracheaABSTRACT
Rhinoliths result from calcification of an endogenous or exogenous nidus within the nasal cavity. Patients typically present symptoms of long-standing unilateral nasal obstruction, pain and foul-smelling discharge. Rhinoliths are most often found on the floor of the nose and maxillary antrum. Rhinoliths are most often found on the floor of the nose and maxillary antrum. Rhinoliths present complications involving erosion or perforation of nasal mucosa, septum and palate. Sinusitis is a rare complication of rhinoliths. The authors experienced a case of frontal sinus rhinoliths in 36 years old man who complained of a headache and had a history of a frontal area trauma. At first we suspected it to be fungal sinusitis or mucocele, but finally confirmed it to be frontal sinus rhinolith after carrying out a frontal sinus osteoplastic operation.