Omega-3 fatty acid regulates inflammatory cytokine/mediator messenger RNA expression in Porphyromonas gingivalis-induced experimental periodontal disease.
BACKGROUND
Porphyromonas gingivalis is strongly implicated in the etiology of adult periodontitis by inducing inflammatory cytokines, resulting in gingival and periodontal tissue inflammation and alveolar bone resorption. This study tested the hypothesis that supplementing the diet with omega-3 fatty acid (omega-3 FA; i.e. fish oil) would exert anti-inflammatory effects in the gingival tissues of P. gingivalis-infected rats.


METHODS
Rats were fed either fish oil or corn oil diets ad libitum for 22 weeks and infected with P. gingivalis strain 381 or strain A7A1-28. After sacrifice, rat gingival tissues were excised and the RNA was isolated and analyzed for proinflammatory mediators [interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6], T helper type 1 and type 2 cytokines [interferon-gamma (IFN-gamma), IL-4, IL-10), antioxidant enzymes [catalase (CAT), superoxide dismutase (SOD)], and genes critical for eicosanoid mediator production [cyclo-oxygenase-2 (COX-2), 5-lipoxygenase (5-LO)] by reverse transcription-polymerase chain reaction using rat-specific primers.


RESULTS
Rats on the omega-3 FA diet exhibited decreased proinflammatory cytokine gene expression (IL-1beta, TNF-alpha) and enhanced IFN-gamma, CAT and SOD messenger RNA expression compared to rats fed a corn oil diet, supporting a diet-induced modulation of host inflammatory reactions. Analyses of alveolar bone resorption in the rats related to gene expression profiles demonstrated significant positive correlations with IL-1beta, IL-6 and COX-2 and negative correlations with CAT and SOD.


CONCLUSIONS
These findings suggest that diets enriched for omega-3 FA modulate the local gingival inflammatory milieu of the host following oral P. gingivalis infection, which impacts on alveolar bone resorption in rats.
Kesavalu
L
L
Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA. kesavalu@dental.ufl.edu
Bakthavatchalu
V
V
Rahman
M M
MM
Su
J
J
Raghu
B
B
Dawson
D
D
Fernandes
G
G
Ebersole
J L
JL
D016301:Alveolar Bone Loss / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control; D000818:Animals; D016866:Bacteroidaceae Infections / Q000378:metabolism / Q000517:prevention & control; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D016207:Cytokines / Q000096:biosynthesis*; D019587:Dietary Supplements; D015525:Fatty Acids, Omega-3 / Q000502:physiology* / Q000627:therapeutic use; D005260:Female; D005395:Fish Oils / Q000627:therapeutic use; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D018836:Inflammation Mediators / Q000378:metabolism*; D053583:Interleukin-1beta / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D010518:Periodontitis / Q000378:metabolism* / Q000382:microbiology / Q000517:prevention & control; D016966:Porphyromonas gingivalis / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000096:biosynthesis
D016207:Cytokines; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D013482:Superoxide Dismutase