Spatially resolved single-cell-based histocytomorphometry for growth plate analysis across multiple species

Area of Science:

• Computational Biology
• Histomorphometry
• Endochondral Ossification

Background:

• Current growth plate assessment methods lack resolution for cellular heterogeneity.
• Endochondral ossification involves complex chondrocyte dynamics crucial for bone growth.
• Existing techniques fail to capture spatial and functional variations in chondrocytes.

Purpose of the Study:

• To develop an automated computational histomorphometric pipeline (GP Pro) for single-cell analysis of growth plate dynamics.
• To quantify chondrocyte kinetics and maturation gradients from routine histological sections.
• To provide a high-throughput tool for studying growth plate pathobiology.

Main Methods:

• GP Pro integrates modules for whole-slide image processing, growth plate segmentation (SAM2), and single-cell lacunae analysis.
• Feasibility testing involved high-throughput analysis of mouse, hamster, and rat knee sections (Safranin-O, H&E).
• Application validation used tibial growth plates from WKY and spontaneously hypertensive rats (SHRs), correlating with micro-CT and histochemistry.

Main Results:

• GP Pro achieves >95% automated processing success, 90.28% chondrocyte identification accuracy, and 3.6s processing time per section.
• Analysis of SHR growth plates revealed increased proliferative chondrocytes and maturation arrest.
• Hypertension-induced cellular changes correlated with decreased primary spongiosa bone volume, indicating compromised osteogenic coupling.

Conclusions:

• GP Pro offers a scalable platform for high-resolution in situ mapping of chondrocyte behavior.
• The tool advances mechanistic studies of endochondral ossification by linking differentiation delays to bone deficits.
• GP Pro has translational potential for diagnosing growth disorders and monitoring therapies across species.