Changes in cartilage and SM
Gross evaluation of cartilage was performed in three studies, which
reported that TA or MPA injected in normal joints showed no changes in
cartilage appearance (Frisbie et al., 1997; Murray et al., 1998; Frisbie
et al., 1998).
Histologic examination of SM was performed in three studies (Frisbie et
al., 1997; Frisbie et al., 1998; Todhunter et al., 1998). MPA promoted
only mild to no significant changes in cellular infiltrate,
proliferation of synovial cells, SM intimal hyperplasia, or fibrous
tissues, having only effects on the decrease of SM vascularity (Frisbie
et al., 1998; Todhunter et al., 1998). Regarding TA, a significant
decrease in inflammatory cell infiltration and intimal cell hyperplasia
was found, as was reduced SM subintimal fibrosis (Frisbie et al., 1997).
Histology of articular cartilage was also reported, and no significant
changes were found after MPA-injected joints in one study (eight-day
follow-up) (Todhunter et al., 1998), while the same corticosteroid
worsened histologic scores of articular cartilages with longer follow-up
(72 days) (Frisbie et al., 1998). TA effects on cartilage histology were
investigated by only one group (Frisbie et al., 1997), which found a
significant decrease in pathological changes associated with TA
treatment.
Articular PG synthesis and GAG content in cartilage were evaluated. MPA
significantly decreased PG and GAG synthesis in normal joints with
increases in the synthesis of small proteoglycan monometers (Todhunter
et al., 1998), while TA caused a significant increase in GAG synthesis
(Frisbie et al., 1997). Total GAG content in cartilage after TA or MPA
treatments was not significantly different from controls. However, TA or
MPA-treated joints demonstrated a significant loss of SOFG staining in
articular cartilage (Frisbie et al., 1997; Frisbie et al., 1998).
MPA injected in normal joints increased collagen and TP synthesis of
joint tissues collected postmortem at eight days of follow-up (Todhunter
et al., 1998).
Biomechanical properties of normal cartilage that received
corticosteroid injections were assessed by Murray et al. (1998), who
performed indentation testing postmortem and evaluated the material
properties of the cartilage of joints receiving MPA. The authors found
that MPA-treated joints were thinner, more compressible, and had less
stiff cartilage than controls.