title: Can the choice of intermediate solvent or resin affect glomerular basement membrane thickness?
abstract: BACKGROUND
  Establishing glomerular basement membrane (GBM) thickness is important in the diagnosis of some renal diseases. It is widely believed that GBM thickness varies according to the processing method, yet there appear to be no published data to support this. In this study we aimed to determine whether the choice of intermediate solvent and embedding resin influenced the thickness of the GBM and to assess the magnitude of any such effect.
  
  
  METHODS
  Subcapsular renal cortical rat tissue was processed for electron microscopy using four different intermediate solvents [propylene oxide (PO), xylene (Xyl), acetone (Ac) or ethanol (Et)], and three epoxy resins [Araldite (Aral), TAAB embedding resin (TER) or TAAB low viscosity resin (TLV)]. GBM thickness was estimated by the orthogonal intercept method.
  
  
  RESULTS
  Compared with PO-Aral embedding, GBM was significantly thinner in Xyl-Aral, Ac-Aral and Xyl-TER, and significantly thicker in PO-TER-, Ac-TER-, Et-TER- and PO-TLV-embedded tissue (P < 0.05 in all cases). No significant difference was seen with Xyl-TLV- and Ac-TLV-embedded tissue. Et-Aral and Et-TLV embedding resulted in poor quality blocks.
  
  
  CONCLUSIONS
  The results suggest that the choice of both intermediate solvent and resin influences shrinkage of the GBM during TEM processing.
authors.affiliation: Department of Histopathology, Cardiff and Vale NHS Trust, UK.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Edwards
authors.forename: David
authors.initials: D
authors.lastname: Griffiths
authors.forename: John
authors.initials: J
authors.lastname: Morgan
authors.forename: Ruth
authors.initials: R
authors.lastname: Pitman
authors.forename: Christopher
authors.initials: C
authors.lastname: von Ruhland