Siriraj Medical Journal (Jan 2009)
Histological and Ultrastructure of the Peripheral Nerve in Cadaveric Embalmed Specimens and in Fresh Cadavers: the Efficacy of Several Fixatives
Abstract
Objective: The study is to observe the histological structure and the ultrastructure of the peripheral nerve from cadaveric embalmed specimens and from fresh specimens by light microscope and by transmission electron microscope. Also to study the efficacy of the embalmed fixative to the tissue. Methods: The peripheral nerves were dissected from the arms of five cadavers of the Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, and from fresh cadavers. Each specimen was bisected, one put into 10% formaldehyde which was prepared for routine H&E staining and study by light microscope. The other was put into 2.5% glutaraldehyde, the best preserved specimen was then chosen to prepare for the TEM study. Results: There is no significant difference between the peripheral nerves of the cadaveric embalmed and the fresh specimens when viewed with the light microscope. On the other hand when viewed by transmission electron microscope, the lipid part of the myelin sheath of the peripheral nerves from the cadaveric embalmed specimens are totally degenerated while the protein part is still intact. While in the fresh specimens which are fixed by 2.5% glutaraldyhyde, there is a complete preservation of the lipid and protein part of the myelin sheath. Conclusion: The cadavers were fixed by excess formalin injection into the femoral artery and embalmed in formalin for at least 1 year, this could not preserve the lipid part of the myelin sheath. However, in the fresh peripheral nerves fixed in 2.5% glutaraldehyde it could preserve the lipid and proetin parts of the myelin sheath perfectly.
