Objective—To investigate in vitro effects of radial
shock waves on membrane permeability, viability, and
structure of chondrocytes and articular cartilage.
Sample Population—Cartilage explants obtained
from the third metacarpal and metatarsal bones of 6
Procedure—Equine cartilage was subjected to radial
shock waves and then maintained as explants in culture
for 48 hours. Treatment groups consisted of a
negative control group; application of 500, 2,000, and
4,000 impulses by use of a convex handpiece (group
A); and application of 500, 2,000, and 4,000 impulses
by use of a concave handpiece (group B). Effects on
explant structure were evaluated by use of environmental
scanning electron microscopy (ESEM).
Membrane permeability was determined by release
of lactate dehydrogenase (LDH). Chondrocyte viability
was assessed by use of vital cell staining.
Comparisons of LDH activity and nonviable cell percentages
were performed by ANOVA.
Results—Cell membrane permeability increased significantly
after application of 2,000 and 4,000 impulses
in groups A and B. A significant decrease in cell viability
was observed for application of 4,000 impulses
in explants of group A. There was no detectable damage
to integrity of cartilage explants observed in any
treatment group by use of ESEM.
Conclusions and Clinical Relevance—Radial shock
waves do not appear to structurally damage articular
cartilage but do impact chondrocyte viability and
membrane permeability. Caution should be exercised
when extremely high periarticular pulse doses are
used until additional studies can determine the longterm
outcome of these effects and appropriate periarticular
treatment regimens can be validated. (Am J
Vet Res 2005;66:1757–1763)
Objective—To evaluate the effects of methylprednisolone acetate (MPA) on proteoglycan production by equine chondrocytes and to investigate whether glucosamine hydrochloride modulates these effects at clinically relevant concentrations.
Sample Population—Articular cartilage with normal gross appearance from metacarpophalangeal and metatarsophalangeal joints of 8 horses (1 to 10 years of age).
Procedures—In vitro chondrocyte pellets were pretreated with glucosamine (0, 1, 10, and 100 μg/mL) for 48 hours and exposed to MPA (0, 0.05, and 0.5 mg/mL) for 24 hours. Pellets and media were assayed for proteoglycan production (Alcian blue precipitation) and proteoglycan content (dimethylmethylene blue assay), and pellets were assayed for DNA content.
Results—Methylprednisolone decreased production of proteoglycan by equine chondrocytes at both concentrations studied. Glucosamine protected proteoglycan production at all 3 concentrations studied.
Conclusions and Clinical Relevance—Methylprednisolone, under noninflammatory conditions present in this study, decreased production of proteoglycan by equine chondrocytes. Glucosamine had a protective effect against inhibition of proteoglycan production at all 3 concentrations studied. This suggested that glucosamine may be useful as an adjunct treatment when an intra-articular injection of a corticosteroid is indicated and that it may be efficacious at concentrations relevant to clinical use.