||Objective: The vascularization of subchondral bone plays a significant role in the progression of knee
osteoarthritis (OA). Treatment with platelet-rich plasma (PRP) has positive effects on cartilage lesions.
However, PRP's efficacy for subchondral bone marrow lesions and the relationship of these lesions to
cartilage are still undiscovered. Therefore, our aims were first to longitudinally investigate the change in
subchondral flow by dynamic contrast enhanced MRI and degeneration of cartilage by MRI T2* in an
anterior cruciate transection rodent (ACLT) model, and second to examine changes in parameters after
intra-articular PRP injection.
Design: A 32-week investigation in 18 rats allocated to sham-control, ACLT with normal saline injection
(ACLT þ NS), and ACLT with PRP injection groups ended with histological evaluation. Another rat was
used as a donor of allogenic PRP.
Results: Compared to the sham-control group, the ACLT þ NS group had higher subchondral blood
volume A (0.051, 95% confidence interval: 0.009, 0.092) and lower venous washout kel
(0.030: 0.055, 0.005) from week 4; lower permeability kep from week 18 (0.954: 1.339, 0.569);
higher cartilage T2* values (1.803: 1.504, 2.102) reflecting collagen loss beginning at week 10. For the PRP
treatment group, subchondral bone marrow A and cartilage T2* decreased from week 10. Histological
results confirmed and were correlated with the MRI findings.
Conclusion: Subchondral hyper-perfusion plays a vital role in the pathogenesis of OA and was associated
with cartilage degeneration. The efficacy of PRP can be observed from reduced perfusion and MRI T2*