Cartilage with subchondral bone was excised in 3 x 3 mm2 cross-sectional area from healthy bovine knees and stained in phosphotungstic acid (PTA) for 0, 4, 8, 12, 16, 20, 24, 28 and 32 hours. XRM imaging was performed after each staining time, analyzed and determined an optimal staining time of 16 hrs and a saturated staining time of 24 hrs for this sample. Polarized light microscopy and second harmonic generation dual-photon microscopy of a histology section from the same sample were analyzed and compared with the matching XRM slice.
Cartilage collagen network from PTA-enhanced XRM was well correlated with histology. We validated the PTAenhanced XRM for the evaluation of the cartilage collagen network non-destructively. The 3D cartilage volume from this technique will provide a non-destructive approach to investigate OA pathology.