Substance P induces interleukin-8 secretion from human dental pulp cells.
OBJECTIVE
The role of neuropeptides in recruiting leukocytes in dental pulps is not known; therefore, we investigated whether interleukin-8 (IL-8) secretion from human pulp cells is increased after stimulation with substance P (SP) or calcitonin gene-related peptide (CGRP).


METHODS
Primary pulp cells exhibiting a fibroblast-like phenotype and an endothelial cell line were stimulated with various doses of SP or CGRP, and IL-8 secretion was measured by enzyme-linked immunosorbent assays.


RESULTS
IL-8 secretion from pulp cells increased significantly at 10(-8) to 10(-4) mol/L of SP stimulation (5- to 13.8-fold; P <.05); however, no significant IL-8 increase with CGRP (up to 10(-4) mol/L) stimulation was observed, nor was there synergistic induction of IL-8 with SP plus CGRP. The IL-8 increase reached its maximum at 8 hours after SP stimulation of the pulp cells. SP at a concentration of 10(-4) mol/L created minimal IL-8 induction in the endothelial cells and no synergistic induction by SP and CGRP.


CONCLUSIONS
Pulp cells may up-regulate IL-8 secretion by SP stimulation, which suggests that SP released in dental pulp may play a role in the influx of leukocytes, attracted by IL-8, into the pulp tissue.
Patel
Tushar
T
School of Dentistry, University of California at Los Angeles, 90095-1668, USA.
Park
Sang Hyuk
SH
Lin
Louis M
LM
Chiappelli
Francesco
F
Huang
George T-J
GT
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D020078:Neurogenic Inflammation / Q000503:physiopathology; D013268:Stimulation, Chemical; D013373:Substance P / Q000494:pharmacology*; D013997:Time Factors
D016209:Interleukin-8; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide