3D Cell Density of Human Knee Meniscus

The knee menisci have important roles in the knee joint. The complete healing of meniscus remains as a challenge in the clinics. Cellularity is one of the most important biological parameters that must be taken into account in regenerative strategies. However, the knowledge on the 3D cellularity of meniscus lacks in the literature. The aim of this study is to quantify the 3D cellular density of the human meniscus in a segmental and regional manner with respect to the laterality.
Human lateral menisci were histologically processed, and stained with Giemsa for the histomorphometric analysis. The cells were counted in an in-depth fashion based on their roundish or flattened morphologies. The cell density in the vascular region (27,199 cells/mm3) was significantly higher as compared to avascular region (12,820 cells/mm3). The fibrochondrocytes density (14,705 cells/mm3) was significantly greater than the fibroblast-like cells density (5,539 cells/mm3). A strong positive correlation was found between fibrochondrocytes and fibroblast-like cells densities. The best-fit equation for the prediction of the fibrochondrocytes density from the fibroblast-like cell density was found to be:
"Fibrochondrocytes density=1.22 × Fibroblast­like cell density +7750". The obtained data shows that the meniscus tissue is heterogeneous in a segmental and regional manner in terms of 3D cellular density.
The present study revealed the segmental and regional 3D cellular density of human knee meniscus with respect to the laterality. This crucial but so far missing information will empower the cellular strategies aiming meniscus tissue regeneration.