Shape, size, and distribution of cell structures by 3-D graphics reconstruction and stereology. I. The regulatory...

Area of Science:

• Cell Biology
• Biophysics
• Neuroscience

Background:

• Conventional electron microscopy (EM) offers limited 2D views, hindering accurate 3D cell morphology assessment.
• Morphometric analysis of thin sections provides incomplete data for complex cell structures and heterogeneous cell populations.
• Understanding astroglial cell volume regulation is crucial for treating brain injury.

Purpose of the Study:

• To overcome 2D imaging limitations for precise 3D cell size and shape determination.
• To quantify volume changes in astroglial cells during hypo-osmolar swelling and Regulatory Volume Decrease (RVD).
• To investigate the relationship between cell volume homeostasis and organelle morphology.

Main Methods:

• Analysis of stereo pairs from high-voltage EM of serial thick sections (0.5 micron) and whole-cell mounts.
• Utilized a novel stereoscopic contouring device to enhance Z-axis resolution by digitizing contours at discrete levels.
• Calculated area and volume changes during osmotic swelling and RVD in rat brain astroglial cell cultures.

Main Results:

• Achieved accurate 3D reconstruction of astroglial cells, providing detailed volume and shape information.
• Quantified volume changes in nucleus, cytoplasm, and organelles (e.g., mitochondria) during swelling and RVD.
• Results for total cell volume changes correlate with previous studies using diffusion-based methods.

Conclusions:

• 3D reconstruction from serial EM sections provides comprehensive cell morphology data, overcoming 2D limitations.
• Astroglial cell swelling and RVD involve coordinated volume changes across cellular compartments and organelles.
• Abnormal organelle volumes may serve as indicators of cellular dysfunction in metabolism, division, or gene expression.