Tissue-selective inflammation in the oral cavity of the rat.
In the current study, carrageenan (CG; 100-1000 μg/site) was injected intraorally in the cheeks of Holtzman or Wistar rats to evaluate the consequences of administration of a non-immunogenic stimulus in the orofacial region. Subsequent inflammation was measured as oedema (increased thickness of the cheek wall using digital calipers), relative to the other cheek injected with saline. Oedema formation and tissue collection for histopathological studies were assessed at 0.5, 1, 2, 3, 4, 6, 24, 48, 72, 96, 120 and 144 h after injection. In parallel, other groups of rats were injected with CG in the hind paw, to provide a reference response. The inhibitor of prostaglandin biosynthesis, indomethacin, and antagonists of histamine, serotonin and NK1 receptors were injected s.c., 0.5 h before CG. CG induced a dose-related oedema more rapidly from 0 to 2 h which lasted for at least 72 h, showing a biphasic profile (peak at 2 and 24 h), compared with the monophasic oedema induced in rat paws (maximal duration of 24 h). Histopathological analysis of the CG-injected cheek revealed oedema formation with little leukocyte recruitment at 1-3 h, mast cell degranulation at 6 h, and a mixed polymorphonuclear and mononuclear cell infiltrate by 24 h. Histamine and serotonin antagonists and indomethacin, but not the NK1 antagonist, decreased cheek oedema in the first 4 h following carrageenan. Taken together, our data indicated important differences in the pattern of inflammation between the oral cavity and the paw which will determine the therapeutic approach to the treatment of inflammatory conditions in the oral cavity.
Dentistry Faculty at Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Taíssa Iolanda Checón
TI
Frade
General Pathology Department of Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Diego Carlos
DC
Dos Reis
General Pathology Department of Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Geovanni Dantas
GD
Cassali
Leukocyte Biology, NHLI, Imperial College, London, UK.
Yeshwant S
YS
Bakhle
Pharmacology Department of Biological Sciences Institute (ICB), Federal University of Minas Gerais, Av. Antonio Carlos 6627, Pampulha, Belo Horizonte, MG, Brazil. janettif@icb.ufmg.br.
Janetti Nogueira
JN
de Francischi
D000818:Animals; D002351:Carrageenan / Q000008:administration & dosage*; D002610:Cheek; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000139:chemically induced / Q000276:immunology* / Q000378:metabolism / Q000517:prevention & control; D006633:Histamine Antagonists / Q000008:administration & dosage / Q000627:therapeutic use; D007213:Indomethacin / Q000008:administration & dosage / Q000627:therapeutic use; D009055:Mouth / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D064729:Neurokinin-1 Receptor Antagonists / Q000008:administration & dosage / Q000627:therapeutic use; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012702:Serotonin Antagonists / Q000008:administration & dosage / Q000627:therapeutic use
D006633:Histamine Antagonists; D064729:Neurokinin-1 Receptor Antagonists; D012702:Serotonin Antagonists; D002351:Carrageenan; D007213:Indomethacin
Carrageenan; Cheek oedema; Histamine; Prostaglandins; Serotonin