Alternations of Metabolic Profiles in Synovial Fluids and the Correlation with T2 Relaxation Times of Cartilage and Meniscus—A Study on Anterior Cruciate Ligament- (ACL-) Injured Rabbit Knees at Early Stage

Abstract

Objectives. To examine the metabolic profiles alterations of synovial fluids from anterior cruciate ligament- (ACL-) injured rabbit knees at early stage and analyze the correlation with T2 relaxation times of cartilage and meniscus. Methods. The right knees of 15 rabbits were selected for the construction of ACL injury models, whereas the contralateral knees served as control group. After 4 weeks, both knees were examined by MRI with quantitative T2 mapping sequence, and the T2 relaxation times of cartilage and meniscus were measured. Then, the synovial fluids were obtained from both knee capsules and performed liquid chromatography-mass spectrometry analysis (LC-MS). Results. The T2 relaxation times of cartilage and meniscus in ACL-injured knees were significantly higher than those in control knees (Cartilage: 41.52 ± 2.98 ms vs 36.02 ± 2.71 ms, P < 0.001; Meniscus: 33.35 ± 3.57 ms vs 27.27 ± 2.10 ms, P < 0.001). Twenty-eight differential metabolites were identified based on a total of 1569 detected signatures between ACL-injured knees and control knees. These differential metabolites primarily implied perturbations in the fluxes of lipids and steroid-based compounds. The Linear regression analysis demonstrated satisfactory correlations between glycerophospholipid metabolism and T2 relaxation times of both cartilage and meniscus in ACL-injured knees (R2 = 0.8204 and 0.8197, respectively). Conclusion. ACL injury of rabbit knees resulted in elevated T2 relaxation times of cartilage and meniscus and perturbed metabolism of various lipids and steroids in synovial fluids, particularly glycerophospholipids. Glycerophospholipid metabolism related compounds could serve as potential biomarkers for early degenerative changes of cartilage and meniscus after ACL injury.

Magnetic Resonance Imaging T2* Mapping of the Talar Dome and Subtalar Joint Cartilage 3 Years After Anterior Talofibular Ligament Repair or Reconstruction in Chronic Lateral Ankle Instability

“…29,52 There is evidence that elevated T2/T2* relaxation values could be associated with the disorganization of collagen and increased water content in the cartilage, which could be indicators of early cartilage degeneration. 43 When compared with T2 mapping, T2* mapping has advantages of shorter acquisition time and higher resolution. 21,44 It was recently used to evaluate articular cartilage.…”

Radiomics Feature Analysis of Cartilage and Subchondral Bone in Differentiating Knees Predisposed to Posttraumatic Osteoarthritis after Anterior Cruciate Ligament Reconstruction from Healthy Knees

“…Therefore, there is a more compelling need to improve diagnostic techniques in order to detect PTOA at an early stage. T2 mapping has made the greatest strides in the evaluation of cartilage degeneration, which is a well-established early indicator of PTOA in patients after ACLR [16][17][18]. However, mean T2 6 BioMed Research International value analysis is somewhat subject to many common limitations, such as dependency of loading [19], sequence type [20], or parameter selection [21].…”