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Easing Pain Isn't Enough:

K-State veterinarians research medication and food to improve treatment of dogs with Osteoarthritis

By Jessica Clark

 

MANHATTAN -- If your normally healthy, active dog who enjoys trips to the park and long days hunting begins to move a little slower, is unwilling to jump or run as she once did or prefers to sit or lie down rather than stand, a trip to the veterinarian may be in order.

These are all symptoms associated with osteoarthritis in dogs. There are different causes, one of them being injury to a ligament that could be caused by a game of Frisbee or a day hunting.

Dr. James K. Roush, associate professor of clinical sciences at Kansas State University's Veterinary Medical Teaching Hospital, is involved in researching medication and food that may change the current methods of treating osteoarthritis in dogs.

"Within six weeks of rupturing a ligament, bone spurs at the edges of joints and loss of joint space are visible on an X-ray. Osteoarthritis develops very fast in dogs after injury to a cruciate ligament, one of the two ligaments in the knee, probably because they stand a little bit bent at the knee instead of straight like a human," Roush said.

Besides sports injuries, osteoarthritis in dogs may be caused by bacterial infections in the joint, and most commonly, growing abnormalities in the joint, Roush said.

Dogs with osteoarthritis may start to get up and move more slowly and be reluctant to bear weight on a limb. Swelling may occur in the joint and they won't move it as freely. They will use other joints to compensate and eventually stop bearing weight on the limb if the arthritis gets bad enough, Roush said.

Common treatments for osteoarthritis include analgesics, anti-inflammatories like aspirin, and chondoprotective agents, drugs that lubricate the joint and protect it to some degree, Roush said.

Analgesics are pain-control agents that can increase the loss of cartilage. Although aspirin can cause gastrointestinal bleeding, there are analgesics that are marketed specifically for dogs that cause less gastrointestinal bleeding than aspirin. Human analgesics, such as ibuprofen or naproxen, should never be used in dogs and can be fatal with a single dose, Roush said.

"If you put a dog on analgesics, they may feel better the next day, but you may be increasing how fast the arthritis develops. If you put the dog on chondoprotectives, they don't get that much better quickly, but they'll be better two years from now than they are today," Roush said.

Roush's research is focused on two parts, a new drug that is marketed currently in Europe for people and a dog food that is higher in N3 fatty acids, higher in fish oil.

"There are some reports on dogs with dermatitis where the dogs were given more N3 fatty acids to change the way they produce oil on the skin. These supplements also happened to help dogs in the study that had osteoarthritis feel better," Roush said.

In a previous study, dogs who had surgery for osteoarthritis were studied. Some of them were on a normal diet and the others were on a diet high in N3 fatty acids. A similar study will be conducted in the next month on clinical patients coming in with osteoarthritis, Roush said.

Roush's current study is testing a medication that doesn't have the side-effects of aspirin on dogs who come in with naturally occurring osteoarthritis and are lame in at least one leg.

In both studies, dogs are walked across a force plate, a 2 foot by 3 foot device embedded into the floor. "It measures how much weight the dog puts on each foot, detecting very subtle changes and lameness by measuring what percentage of their body weight they place on a particular limb," Roush said.

If the studies are successful, further testing by the Food and Drug Administration would be conducted. In the near future, the FDA could potentially approve the first anti-arthritic drug that works at a basic molecular level without the side effects of analgesics, benefiting dogs with osteoarthritis, Roush said.

Roush's orthopedic colleague also involved in the research is Dr. Walter Renberg, department of clinical sciences at K-State's College of Veterinary Medicine.

March 19, 2002