There are lots of reports on the effects of PSGAGs and HA on
equine cartilage - but much of the work is in vitro - which
must be cautiously extrapolated to live animals! Even the
literature on the intra-articular and intramuscular
administration shows conflicting results. There is an
interesting study in racehorses in England with flexor
tendon injuries: 76% of the PSGAG treated horses compared to
46% of rest-only horses returned to racing, but the
differences were not statistically significant. The
interesting point is that 50% of the PSGAG horses reinjured
their tendons, while only 31% relapsed in the conservatively
managed group.
I can find nothing on the preventative use of PSGAGs in the
horse - all that work has been done in dogs with hip
dysplasia - where PSGAGs appears more beneficial in the dog
with early dysplasia than the one with advanced arthritis.
In dogs we have pretty good ideas on breeds that are likely
to have HD and we can screen for them at a young age. I
don't think this is so feasible in equine atheletes.
The nutriceutical issue is being debated in the veterinary
profession - there are letters to the editor on this topic
in the April 15 and July 1 issues of the Journal of the
American Veterinary Medical Association. It will be
interesting to see in a few years where this leads!
Trisha Dowling, DVM, MS
Diplomate, ACVIM and ACVCP
Associate Professor, Veterinary Clinical Pharmacology
Western College of Veterinary Medicine
Saskatoon, Sask.