Laboratory study demonstrates that acid-free glyoxal reliably preserves glomerular ultrastructure in human renal tissue, suggesting a safer alternative to toxic glutaraldehyde.
Key Points
To evaluate whether acid-free glyoxal provides adequate ultrastructural preservation for renal transmission electron microscopy and allows diagnostic recovery from paraffin-embedded tissue compared with glutaraldehyde.
Normal human renal cortical tissue from nephrectomy specimens was fixed in acid-free glyoxal for 24, 48, or 72 hours, with 2.5% buffered glutaraldehyde serving as the control.
Transmission electron microscopy was performed on direct and reprocessed paraffin-embedded samples to assess podocyte foot processes, slit diaphragms, endothelial fenestrations, and the glomerular basement membrane.
Specimens were further evaluated for compatibility with conventional histology, automated immunohistochemistry, and exploratory immunofluorescence.
Fixation for 24 hours preserved the primary components of the glomerular filtration barrier, while 48 and 72 hours substantially improved preservation of slit diaphragms and endothelial fenestrations with balanced contrast.
Tissue recovered from paraffin-embedded blocks yielded sufficient ultrastructural detail for standard diagnostic pathology, whereas automated immunohistochemical reactivity was reduced across tested markers.