title: Activation of microglial cells in the trigeminal subnucleus caudalis evoked by inflammatory stimulation of the oral mucosa.
abstract: To study the inflammatory hyperplasia induced by an acute noxious stimulation of oral mucosa with 5% formalin (5%FOR), we performed an immunohistochemical study on the expression of TNFá in the intermolar region of the dorsal lingual eminence (IDLE), and Iba1 and phosphorylated (phospho)- p38 MAPK involved with central nervous system microglial activation in the trigeminal subnucleus caudalis (Vc). The present study observed significantly increased expression of TNFá at either 1h or 24h of 5%FOR nociception, as well as sustained TNFá immunoreactivity in the IDLE. On the other hand, at either 1h or 24h 5%FOR nociception, Iba1- immunoreactive (IR) cells in the Vc were significantly increased after inflammatory stimulation of the IDLE; the increase was more evident at 24h 5%FOR nociception. By using the double-label immunofluorescence technique, the findings in particular demonstrated a significant increase in the number of phospho-p38 MAPK- and Iba1-IR coexpressed cells in the Vc at 24h 5%FOR nociception. The results suggest that 24h persistent microglial activation in subnuclei zonalis and gelatinosus of the Vc is evoked by 5%FOR noxious stimulation of the IDLE oral mucosa, thereby the present study indicates that the MAPK expression plays important roles in microglial activation related with central sensitization and inflammatory hyperalgesia.
authors.affiliation: Department of Oral Anatomy, Osaka Dental University, Kuzuha Hanazono 8-1, Hirakata, Osaka 573-1121, Japan.
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Huang
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakatsuka
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Iwai
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D005557:Formaldehyde / Q000009:adverse effects* / Q000494:pharmacology*; D006930:Hyperalgesia / Q000139:chemically induced / Q000378:metabolism; D007249:Inflammation / Q000139:chemically induced* / Q000378:metabolism; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D017628:Microglia / Q000502:physiology*; D023421:Models, Animal; D009061:Mouth Mucosa / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014275:Trigeminal Caudal Nucleus / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: C100745:Aif1 protein, rat; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins; D014409:Tumor Necrosis Factor-alpha; D005557:Formaldehyde; D048051:p38 Mitogen-Activated Protein Kinases