An Alternative Approach for Sample Preparation with Low Cell Number for TEM Analysis.

Area of Science:

• Cell Biology
• Microscopy Techniques
• Stem Cell Research

Background:

• Transmission Electron Microscopy (TEM) is crucial for cellular ultrastructure analysis.
• Analyzing rare cell populations, such as hematopoietic stem cells (HSCs), with TEM is challenging due to high cell number requirements.
• Existing methods for scarce samples lack sufficient quantitative data.

Purpose of the Study:

• To develop a novel and efficient sample preparation protocol for TEM analysis of rare cell populations.
• To enable quantitative TEM analysis from limited biological samples.
• To overcome the limitations of current TEM preparation methods for scarce cell numbers.

Main Methods:

• A new protocol utilizing Evans blue staining after paraformaldehyde-glutaraldehyde (PFA-GA) fixation for visualizing cell pellets.
• Embedding the stained cell pellet in agarose for easier handling and sectioning.
• Utilizing a significantly reduced cell number (10,000 HSCs) compared to traditional methods.

Main Results:

• Successful TEM analysis was achieved with a low cell number (10,000 HSCs).
• Well-preserved cellular morphology and visible ultrastructural details (Golgi complex, mitochondria) were observed.
• The protocol facilitates the observation of numerous cells within clusters in ultra-thin sections.

Conclusions:

• The developed protocol is efficient, easy to perform, and reproducible for TEM sample preparation.
• This method allows for both qualitative and quantitative TEM analysis of rare cell populations from limited samples.
• It significantly expands the applicability of TEM for studying scarce cell types like HSCs.