57Freund’s adjuvant (CII-CFA) also leads to paw redness and swelling within four
weeks in CIA mice. Although it seems that CIA mice develop the inflammatory
symptoms more significant than BIA mice, establishment of such a novel experi-
mental model with a typical, albeit mild, inflammatory synovitis/arthritis pheno-
type might help elucidate the pathogenic mechanism of RA.
To further identify the pathological alterations occurring in the synovium, we
conducted the histopathological analysis parallelly in BIA and CIA mice. From
the histochemical staining of tissue sections prepared from the inflamed syno-
vial and articular tissues, we did not found any forms of the articular damage and
subintimal fibrosis, but observed some extents of the multilayer intimal hyperpla-
sia and mild synovial infiltration. The lymphocytic infiltration is nearly identical in
BIA and CIA mice, but a higher degree of intimal hyperplasia occurs in CIA mice.
The phenotypical manifestations of inflammatory lesions are, therefore, mirrored
by histological alterations in the synovial hyperplasia.
An alternative mouse synovitic model, so-called BIA-CIA mice, that was estab-
lished by live bacterial feeding and synchronous intradermal CII-CFA injection,
was found to eventually develop a typical synovitis after four weeks, but with
only mild morphological lesions and less histological damage than CIA mice.
Cotreatment of mice by intra-articular CII-CFA injection with live bacterial feed-
ing also lead to the alleviated synovial inflammation and histological alterations
within three days. While CIA mice show the more severe lymphocytic infiltration,
BIA-CIA mice exhibit the mild lymphocytic infiltration. These results implied
that there might be immune suppression or immune protection in BIA-CIA mice,
which could be originated from the inhibition of innate immune functions by bac-
terial products.
5.2.2.2 Global Cytokine Upregulation and Enhanced NO Production
upon Bacterial Infection and/or CII-CFA Immunization
To follow up the immunological profile of inflammatory pathogenesis, we ana-
lyzed as many as 40 kinds of proinflammatory cytokines among modeling mice.
As results, almost all proinflammatory cytokines are upregulated in BIA and CIA
mice, among which IFNγ, interleukins, and colony-stimulating factors are signifi-
cantly upregulated. However, BIA-CIA mice show an overall downregulation of
proinflammatory cytokines including TNFα, IFNγ, IL-1β, IL-6, and IL-10. These
results revealed a direct association of the up/downregulation of proinflammatory
cytokines with the enhancement/attenuation of inflammatory lesions.
To monitor the dynamic change of NO during bacterial feeding and/or CII-
CFA injection, we determined the time course fluctuations of serum NO levels
in modeling mice. As results, bacterial feeding allows the gradual elevation and
maintenance of steady-state high NO levels, whereas CII-CFA injection leads to
the formation of double NO peaks, occurring immediately after the primary chal-
lenging on the 1st day and boosting on the 21st day. Interestingly, BIA-CIA mice
also exhibit the double NO peaks similar with CIA mice, but the NO levels are
5.2 ART Mitigates Bacteria/Collagen-Induced Synovitis