Immunoelectron microscopy on epoxy sections without deplasticizing to detect glomerular immunoglobulin and complement...

Area of Science:

• Nephrology
• Immunopathology
• Electron Microscopy

Background:

• Immunoelectron microscopy (IEM) is crucial for diagnosing kidney diseases.
• Traditional IEM requires deplasticizing epoxy-embedded samples, which can damage ultrastructure.
• Detecting antigens like immunoglobulins and complement C3 in renal biopsies is vital.

Purpose of the Study:

• To develop and validate a novel IEM method for renal biopsies.
• To enable immunolabeling of immunoglobulins and complement C3 on epoxy sections without etching.
• To assess ultrastructural preservation and antigen detectability compared to traditional methods.

Main Methods:

• Studied 20 renal biopsies using immunoelectron microscopy (IEM) on epoxy-embedded sections.
• Utilized increased DMP-30 accelerator concentration for immunogold labeling of immunoglobulins and C3.
• Sections were stained with tannic acid, uranyl acetate, and lead citrate; compared with immunofluorescence (IF) on frozen sections.

Main Results:

• Successfully performed immunolabeling of immunoglobulins and C3 on epoxy sections without etching or deplasticizing.
• Demonstrated higher sensitivity of IEM compared to IF in detecting smaller antigen amounts in some IgA-nephritis cases.
• Achieved ultrastructural preservation comparable to standard epoxy embedding.

Conclusions:

• The novel IEM method provides excellent immunolabeling with near-optimal ultrastructure.
• This technique is particularly valuable for limited biopsy material, enhancing diagnostic capabilities.
• This represents the first successful immunolabeling of immunoglobulins on non-etched epoxy sections.