Nitric oxide inhibition normalizes splenocyte interleukin-10 synthesis in murine thermal injury
L. M. Napolitano and C. Campbell
Department of Surgery, University of Massachusetts, Worcester.
OBJECTIVE: To examine the effect of nitric oxide inhibition on cytokine
production and immunologic function in a murine thermal-injury and an
alcohol (ETOH)-ingestion model. DESIGN: Randomized controlled experiment.
SETTING: University surgical research laboratory. ANIMALS: Forty male
Balb/C mice. INTERVENTIONS: Animals were randomized to four groups: normal
saline solution-sham (NS-sham), ETOH-sham, NS-burn, and ETOH-burn. Animals
received 20% ETOH or NS daily for 14 days by gavage. A 20% full-thickness
burn was induced 4 hours after the last dose of ETOH or NS was
administered. Animals were killed 4 days after the burn was induced. MAIN
OUTCOME MEASURES: Splenocytes were harvested and stimulated with the
mitogens lipopolysaccharide or concanavalin A. These mitogen-stimulated
splenocyte cultures had the addition of exogenous N-monomethyl-L-arginine
(2.5 or 10 micrograms/mL), a nitric oxide synthase inhibitor. Splenocyte
production of interleukin-10 (IL-10), interferon-gamma, nitrite, and
prostaglandin E2 were measured, and lymphocyte proliferative response was
examined. RESULTS: Interleukin-10 and interferon-gamma production were
significantly suppressed in thermal injury, and lymphocyte proliferative
response was markedly reduced. Exogenous N-monomethyl-L-arginine normalized
splenocyte IL-10 production in a dose-dependent manner in NS-burn and
ETOH-burn groups, improved lymphocyte proliferative response, and
significantly decreased splenocyte nitrite production. Interferon-gamma
release was not up-regulated by N-monomethyl-L-arginine. CONCLUSIONS:
Thermal injury is associated with a suppression of splenocyte IL-10
production and lymphocyte proliferative response. Inhibition of nitric
oxide synthesis normalized IL-10 production and significantly improved
splenocyte proliferative response. These data suggest that nitric oxide is
an important modulator of cytokine regulation and immunologic function in
thermal injury, thereby ultimately influencing host defense.
