Effect of intramuscularly administered polysulfated glycosaminoglycan on articular cartilage from equine joints injected with methylprednisolone acetate.

The study investigates the impact of polysulfated glycosaminoglycan, when administered intramuscularly, on the articular cartilage of horses treated with a corticosteroid, methylprednisolone acetate. The paper suggests that despite corticosteroids being helpful in treating equine joint disorders, they can alter the biochemical and morphological properties of articular cartilage, to which the chondroprotective drugs might counteract.

Methodology

• The study involved twenty-one ponies which were randomly assigned to one of three groups.
• Group 1 (8 ponies) were treated with methylprednisolone acetate (MPA; 0.2 mg/kg of body weight) and a saline solution, both given intra-articularly, and the saline solution also given intramuscularly (IM).
• Group 2 (9 ponies) received both MPA (same dosage as group 1) and polysulfated glycosaminoglycan (GAG; 2 mg/kg).
• The control group (Group 3, 4 ponies) was given a saline solution both intra-articularly and IM.
• The corticosteroid or saline solution was injected into the middle carpal joint on the first day. The polysulfated GAG or saline solution was then administered IM at the same time, and the dosage was repeated every three days for 20 days.

Results

• Three weeks after the initial injection, the ponies were euthanatized and their cartilage was examined.
• The researchers found that the articular cartilage in younger ponies was significantly more susceptible to the proteoglycan-depleting effects of MPA.
• The study showed that the ponies below 10 years old in groups 1 and 2 had significantly lower GAG content in their articular cartilage than those in the control group.

Observations

• The research indicates that the systemic treatment with polysulfated GAG did not protect against proteoglycan loss in the articular cartilage, contrary to the expectation that the drug would mitigate some of the damaging effects of corticosteroids on the cartilage.