Increase in excitatory amino acid concentration and transporters expression in osteoarthritic knees of anterior cruciate ligament transected rabbits

SummaryObjectiveThe present study aimed to determine the role of excitatory amino acids (EAAs) and EAA transporters (EAATs) in an osteoarthritis (OA) model of rabbit knees.MethodsOA was induced in New Zealand white male rabbits by anterior cruciate ligament transection (ACLT) in one knee of one hind limb; the other knee left unoperated. Rabbits that received ACLT of knee were assigned to the ACLT group (n=6), while a sham-operated group (n=6) underwent arthrotomy with no ACLT. Six naïve rabbits that received no surgery were used as normal control. The width of the knee joint was measured to determine the severity of joint inflammation. Before operation and at 10, 20, and 30 weeks after operation, knee joint dialysates were collected by microdialysis and assayed for EAAs by high-performance liquid chromatography. Gross morphology and histopathology and EAATs glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) expression in the articular cartilage of the knees were evaluated by immunohistochemistry and western blot analysis.ResultsIn the ACLT knees, a significant increase in the joint width was observed (5.3±0.9mm, P