Crystals generated from lactic acid treated micronized bone.

Human knee synovial fluid was collected from a donor that was diagnosed with CPPD, containing crystals seen under normal (A) and polarized light (B) microscopy. Synovial fluid from a second male donor without crystals present was mixed with 500mMol of lactic acid (LA) and 100mg/ml of micronized mineralized bone (mBone), which produce birefringent crystals after 5 days of incubation at 37°C (C, D). Using 85% lactic acid exposure to micronized mineralized bone, rhomboid crystals are noted to form initially (around 18 hours) followed by rod shaped crystals by 48 hours in solution (E). These crystals in lactic acid also exhibit birefringence under polarized light (F) and are further stable in this form for at least a month. Crystal morphologies of lactic acid combine with calcium phosphate (G, H) and hydroxyapatite (I, J) are also represented, with distinctly different morphologies present. All images captured using 40x objective.