Localization of substance P-induced upregulated interleukin-8 expression in human dental pulp explants.
OBJECTIVE
To localize ex vivo expression of interleukin-8 (IL-8) induced by substance P (SP) in human dental pulps.


METHODS
Intact caries-free, freshly extracted third molars (n = 20) were collected from patients (15-25 years old). The teeth were split and pulpal tissue was obtained and stored in Dulbecco's modified Eagle medium. Human dental pulp tissue explants were stimulated with SP. Expression of IL-8 in pulp explants was detected and localized by immunohistochemistry.


RESULTS
Moderated IL-8 immunoreactivities were detected mainly in the cell-rich zone in pulp tissues 12 h after tumour necrosis factor alpha (TNF-alpha) stimulation (positive controls), whereas only weak IL-8 expression was observed in tissues stimulated with SP at the same time interval. These data did not differ from those in negative controls. Increased IL-8 expression in pulp explants after 24 h of SP stimulation was noted compared with negative controls and located in fibroblast-like cells, blood vessel-associated cells and extracellular matrix in the central zone and cell-rich zone of pulp explants. Tissues stimulated with TNF-alpha for 24 h (positive controls) revealed weak IL-8 immunoreactivities with altered cell morphology.


CONCLUSIONS
Substance P induces IL-8 expression and was located in fibroblast-like pulp cells, blood vessel-associated cells and extracellular matrix of human dental explants. These data support the hypothesis that neuropeptide (SP) coordinates the modulation of pulpal inflammation via up-regulating chemokine IL-8.
Huang
G T-J
GT
Division of Endodontics, College of Dental Surgery, Dental School, University of Maryland, Baltimore, MD, USA.
Lee
H W
HW
Lee
H S
HS
Lee
G H
GH
Huh
S Y
SY
Choi
G W
GW
Park
S H
SH
D000293:Adolescent; D000328:Adult; D048429:Cell Size / Q000187:drug effects; D003782:Dental Pulp / Q000098:blood supply / Q000187:drug effects* / Q000276:immunology; D005109:Extracellular Matrix / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000187:drug effects* / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D013373:Substance P / Q000494:pharmacology*; D013997:Time Factors; D046509:Tissue Culture Techniques; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects*
D016209:Interleukin-8; D018377:Neurotransmitter Agents; D014409:Tumor Necrosis Factor-alpha; D013373:Substance P