Tissues such as central nervous system and eyes require special care upon removal. Artefacts induced by rough handling and poor fixation can greatly impede interpretation of histological changes in these organs.
Brain: Lesions in the brain can be localised to focal areas, and the entire intact brain should always be submitted. It is very important to preserve the mid-brain and hind-brain in cases submitted for TSE evaluation.
Eyes: Eyes need to be removed immediately after death, as autolytic change will affect the retina within 10 minutes of anoxia. Good retinal morphology is critical for diagnosis of most cases of ocular blindness. Eyes need to be trimmed of extraocular tissue and muscle before fixing, but leave the optic nerve in place. Intra-vitreous injection of formalin (0.25 ml in a dog or cat, 2 ml in a horse) can be used to optimise retinal histopathology; alternatively a specialist fixation protocol (e.g. use of Bouin’s or Davidson’s fixative) can be pursued.
Screw-top plastic pots, and larger sealable buckets containing 10% formalin. The ratio of formalin to tissue should be 10:1.
All samples must be shipped in leak-proof, sealed containers with appropriate labelling (i.e. name, date, specimen/site). Sample containers and shipping materials can be ordered from Gribbles Veterinary Pathology.