Résumé
OBJECTIVES: Allergic rhinitis (AR) is a chronic upper respiratory tract disease that inflames the mucous membranes of the nose and occurs when circulating inflammatory cells including eosinophils and basophils migrate to and accumulate in the inflammation area by passing through the interstitium and capillary walls. To pass through these barriers, the inflammatory cells degrade extracellular matrix proteins. Matrix metalloproteinases (MMPs) released by inflammatory cells mediate the degradation of these proteins. MMPs have synthetic inhibitors and doxycycline, a tetracycline antibiotic, inhibits MMPs. This study investigated the efficiency of intranasal doxycycline in decreasing the symptoms and inflammatory cell infiltration in an animal model of AR. METHODS: AR was created in female Wistar rats by repeated intranasal challenge with ovalbumin by intraperitoneal injection. For 15 days, topical intranasal doxycycline was administered one hour before ovalbumin administration. Following intranasal administration, nasal symptoms were scored and the nasal mucosae of all rats were evaluated histopathologically. To investigate tissue changes, hematoxyline-eosin and Alcian blue/periodic acid Schiff stains were used. As well, cilia loss, goblet cell changes, vascular congestion, vascular proliferation, inflammatory cell infiltration, eosinophil infiltration and the degree of hypertrophy in chondrocytes were evaluated with light microscopy. RESULTS: Typical symptoms of AR were decreased by intranasal doxycycline administration. These effects were stable after repeated intranasal ovalbumin administration. Histological evaluation of doxycycline treated rats did not reveal typical inflammatory changes associated with AR. CONCLUSION: MMPs may have crucial functions in AR and topical intranasal doxycycline, which decreases inflammatory cell infiltration, may offer an alternative therapy for AR.
Sujets)
Animaux , Femelle , Humains , Rats , Administration par voie nasale , Granulocytes basophiles , Vaisseaux capillaires , Chondrocytes , Cils vibratiles , Agents colorants , Doxycycline , Granulocytes éosinophiles , Oestrogènes conjugués (USP) , Protéines de la matrice extracellulaire , Cellules caliciformes , Hypertrophie , Inflammation , Injections péritoneales , Inhibiteurs de métalloprotéinases matricielles , Matrix metalloproteinases , Microscopie , Modèles animaux , Muqueuse , Muqueuse nasale , Nez , Ovalbumine , Rat Wistar , Maladies de l'appareil respiratoire , Rhinite , TétracyclineRésumé
To determine the neuroprotective effects of Ginkgo biloba extract [EGb761] and Selenium [Se], and the combination of these agents on ischemia/reperfusion [I/R] injury in a rat model of transient global cerebral I/R. This experimental study took place in the Animal Research Laboratory at Dokuz Eylul University, Izmir, Turkey in the year 2006. Fifty rats were subjected to cerebral I/R induced by right carotid artery occlusion technique for a duration of 45 minutes, and then were treated with EGb761 [50 mg/kg/day, ip] and Se [0.625 mg/kg, ip], alone or in combination for 14 days after surgery. Superoxide dismutase, and glutathione peroxidase activities were measured in the hippocampal tissues from 25 animals. Histopathological examinations were also carried out under light and electron microscopy from the rest of animals. The results suggest that EGb761 has a potent neuroprotective effect against cerebral I/R induced injury in rat brain that is comparable with that of Se. However, the combined use of EGb761 and Se does not further protect from neuronal injury when compared with the use of both agents alone. Our results suggest that administration of EGb761, Se and its combination with EGb761 have significant neuroprotective effects on I/R injury in rats via suppression of oxidative stress