In vitro method for 3D morphometry of human articular cartilage chondrons based on micro-computed tomography

Summary Objective The aims of this study were: to i) develop a novel sample processing protocol to visualize human articular cartilage (AC) chondrons using micro-computed tomography (μCT), ii) develop and validate an algorithm to quantify the chondron morphology in 3D, and iii) compare the differences in chondron morphology between intact and osteoarthritic AC. Method The developed protocol is based on the dehydration of samples with hexamethyldisilazane (HMDS), followed by imaging with a desktop μCT. Chondron density and depth, as well as volume and sphericity, were calculated in 3D with a custom-made and validated algorithm employing semi-automatic chondron selection and segmentation. The quantitative parameters were analyzed at three AC depth zones (zone 1: 0-10%; zone 2: 10-40%; zone 3: 40-100%) and grouped by the OARSI histological grades (OARSI grades 0-1.0, n =6; OARSI grades 3.0-3.5, n =6). Results After semi-automatic chondron selection and segmentation, 1,510 chondrons were approved for 3D morphometric analyses. The chondrons especially in the deeper tissue (zones 2 and 3) were significantly larger ( p p Conclusion We have developed a novel sample processing protocol for chondron imaging in 3D, as well as a high-throughput algorithm to semi-automatically quantify chondron/chondrocyte 3D morphology in AC. Our results also suggest that 3D chondron morphology is affected by the progression of osteoarthritis.