Chronic ingestion of Porphyromonas gingivalis induces systemic nitric oxide response in mice.
BACKGROUND
Porphyromonas gingivalis induces nitric oxide (NO) production in various cells, systemic NO elevation being expected in chronic oral challenge.


METHODS
Groups of BALB/c mice were inoculated orally with either live P. gingivalis ATCC 33277 or sterile broth on days 0, 2 and 4, with or without later administration of the inducible nitric oxide synthase (iNOS) inhibitor 1400W. Plasma and tissues were harvested on day 42 for assays of tumor necrosis factor-alpha (TNF-alpha), nitrite and nitrate (NOx) and tissue NO, or histology and iNOS immunohistochemistry.


RESULTS
No signs of gingivitis were observed, but plasma NOx was significantly elevated (P = 0.028) as was TNF-alpha (P = 0.079) in P. gingivalis-inoculated animals compared with controls, NOx being reduced when 1400W was used. NO production in organs showed a similar trend, with significant elevation in liver (P = 0.017) and kidneys (P = 0.027), whereas concomitant treatment of inoculated animals with 1400W caused significant reductions in NO in aorta (P = 0.008) and kidneys (P = 0.046). Sham-inoculated 1400W-treated animals had significantly increased plasma NOx (P = 0.004) and liver NO (P = 0.04). NOx in plasma correlated significantly with NO production in lungs (0.35, P = 0.032) and kidneys (0.47, P = 0.003). Immunohistochemistry demonstrated iNOS activity in many tissues in all groups.


CONCLUSIONS
Repeated oral administration of P. gingivalis induced systemic NO and NOx production in mice, probably by activating iNOS as suggested by the response to 1400W.
Nemec
A
A
Veterinary Faculty Small Animal Clinic, University of Ljubljana, Ljubljana, Slovenia. ana.nemec@vf.uni-lj.si
Pavlica
Z
Z
Crossley
D A
DA
Sentjurc
M
M
Jerin
A
A
Erzen
D
D
Vrecl
M
M
Majdic
G
G
Zdovc
I
I
Petelin
M
M
Skaleric
U
U
D000578:Amidines / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000737:chemistry / Q000473:pathology; D001596:Benzylamines / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D016166:Free Radical Scavengers / Q000378:metabolism*; D005881:Gingiva / Q000737:chemistry / Q000473:pathology; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry / Q000473:pathology; D008099:Liver / Q000737:chemistry / Q000473:pathology; D008168:Lung / Q000737:chemistry / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009055:Mouth / Q000382:microbiology*; D009566:Nitrates / Q000032:analysis / Q000097:blood; D009569:Nitric Oxide / Q000032:analysis / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000032:analysis / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000032:analysis / Q000097:blood; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D011897:Random Allocation; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000737:chemistry / Q000473:pathology; D013997:Time Factors; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D000578:Amidines; D001596:Benzylamines; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; C104820:N-(3-(aminomethyl)benzyl)acetamidine; D009566:Nitrates; D009573:Nitrites; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse