63unambiguous that both drugs can suppress NO production, and administration of
RAP and/or ART can effectively block the onset of synovitis. So there should be
an association between the increase of arthritic inflammation and the decrease of
NO production.
Antibacteria by CEF, anti-inflammation by diluted alcohol, proapoptosis by
phytol, or a combination of multidrugs in live bacterial feeding mice improves
the inflammatory feature of synovial tissues, which could be reflected by the nor-
malization of hypoxic parameters. CEF can dramatically decrease those hypoxic
parameters to the values comparative to the control. Phytol, alcohol, or their
combinations also normalize, more or less, the hypoxic parameters. Support
evidence of alcohol beneficial to antiarthritis is from a clinical cohort demon-
strating that alcohol consumption is inversely associated with the risk and sever-
ity of RA (Maxwell et al. 2010 ). On the other hand, phytol as an oxidative burst
inducer was used for treatment of experimental arthritis in rats, by which autoim-
mune responses are suppressed and both acute and chronic arthritis ameliorated
(Hultqvist et al. 2006 ).
We observed the remarkable synovial hyperplasia and angiogenesis from the
histochemical analysis of articular sections. Angiogenesis is an early event in the
inflammatory joint, which enables the activated monocytes entering the synovium
and expanding them throughout a pannus via the recruitment of endothelial cells,
eventually resulting in cartilage degradation and bone destruction (Kennedy et al.
2010 ). Hypoxia can induce the expression of angiogenesis-related genes including
HIF-1α and VEGF (Kasuno et al. 2004 ). NO can also activate HIF-1α under the
normoxic conditions (Natarajan et al. 2003 ). So we concluded that NO is eligible
as a hypoxic inducer capable of initiating angiogenesis and hyperplasia.
The synovium itself is a relatively hypoxic tissue, in which O 2 tension in
cartilage ranges from 7 % (53 mmHg) in the superficial layer to less than 1 %
(7.6 mmHg) in the deep zone (Fermor et al. 2007 ). NO can also accelerate its
own consumption by increasing its entry into red blood cells (Han et al. 2003 ).
NO inhibits the mitochondrial enzyme COX in competition with O 2 , leading to so-
called a “metabolic hypoxia” situation, in which cells cannot use O 2 although it is
available (Xu et al. 2005 ). High levels of NO inhibit cell respiration by binding to
COX, whereas slow and small-scaled NO release can stimulate mitochondrial bio-
genesis in diverse cell types (Nisoli and Carruba 2006 ). Our results also indicated
that high NO levels are correlated with low SpO 2 , hence validating NO conveying
signals for angiogenesis and hyperplasia.
Due to the hypoxic induction, blood sugars are anaerobically catabolized
and necessarily converted to LA by glycolysis, which can be accumulated in the
bloodstream unless O 2 supply is rehabilitated. By monitoring the dynamic changes
of NO and LA, we observed a proportional fluctuation of NO with LA in arthritic
modeling mice. The high LA level is a new and simple parameter for quantify-
ing hypoxia and indicating transversion from normoxia to hypoxia. Furthermore,
it is known that hypoxia can activate HIF-1α, which in turn binds to the promoter
of downstream hypoxia-inducible genes such as VEGF for starting transcription
and translation (Olson and van der Vliet 2011 ). We detected the overexpression of
5.2 ART Mitigates Bacteria/Collagen-Induced Synovitis