Mechanism of action of genicular artery embolization in a rabbit model of knee osteoarthritis.

OBJECTIVES: To establish a rabbit osteoarthritis model for genicular artery embolization (GAE) experiments and to investigate the cellular mechanism of action of this novel procedure for interventional radiologists. METHODS: Rabbit knee osteoarthritis was surgically modeled by anterior cruciate ligament transection and medial partial meniscectomy of the bilateral hindlimbs followed by 10 weeks of incubation. Rabbits exhibiting synovitis on magnetic resonance imaging were randomly divided into two groups: the bilateral GAE group and the control (sham procedure) group. Four weeks later, the rabbits' mobility (moving time, sec/10 min) and the histopathological features of each knee were assessed, and inter-group differences were evaluated using Student's t-test and ordinal/linear logistic models with generalized estimating equations. RESULTS: Osteoarthritis modeling and endovascular procedures were successful in 15 of 20 rabbits (8 and 7 in the GAE and control groups, respectively). There was no significant difference in moving times between the two groups (p = .958). The degree of structural cartilage damage was similar in both groups (p = .780). However, the synovial proliferation (p = .016), synovial hypertrophy (p < .001), and villous hyperplasia of the synovial stroma (p = .002) scores were significantly lower in the GAE group than in the control group. The CD3+ cell density (p = .018) and CD3 + cell-infiltrated area (p = .019) were also significantly lower in the GAE group than in the control group. CONCLUSION: GAE can limit inflammatory processes in the synovium of osteoarthritis-affected knees. KEY POINTS: Surgical transection of the anterior cruciate ligament and medial partial meniscectomy of rabbit knees provides a useful animal model for research of genicular artery embolization. Osteoarthritic knees treated by genicular artery embolization showed milder synovial proliferation (p = .016), synovial hypertrophy (p < .001), and villous hyperplasia of the synovial stroma (p = .002) than the untreated knees. Osteoarthritic knees treated by genicular artery embolization presented lower CD3+ cell density (p = .018) and CD3+ cell-infiltrated area (p = .019) in the synovium than the untreated knees.