Effects of autolysis and prolonged formalin fixation on histomorphology and immunohistochemistry of normal canine brain tissue: an experimental study.
J Vet Diagn Invest
; 36(2): 169-176, 2024 Mar.
Article
em En
| MEDLINE
| ID: mdl-38212877
ABSTRACT
CNS tumor diagnosis in dogs often relies on immunohistochemistry (IHC) given similar histologic features among tumors. Most CNS tissue samples encountered by diagnostic pathologists are collected during autopsy, and postmortem specimens can be susceptible to autolysis and prolonged formalin fixation, both of which have the potential to influence IHC results and interpretation. Here we evaluated the effects of experimentally controlled autolysis induced by delayed tissue fixation (sections of brain held for 2, 4, 8, 12, 24, 48, and 72 h in 0.9% NaCl at either room temperature or 37°C prior to fixation) as well as the effects of prolonged formalin fixation times (1 wk, 1 mo, 2 mo) on a panel of 8 IHC markers (CNPase, GFAP, Iba1, OLIG2, PGP9.5, MAP2, NeuN, synaptophysin) relevant to brain tumor diagnosis. Prolonged fixation of up to 2 mo had no detrimental effect on any immunomarker except NeuN, which had reduced immunolabeling intensity. Delayed fixation led to autolytic changes as expected, on a gradient of severity corresponding to increased time in saline prior to fixation. Several immunomarkers should be used with caution (CNPase, OLIG2) or avoided entirely (MAP2, NeuN) in markedly autolyzed brain and brain tumor tissues. Our results suggest that autolysis has minimal effect on most immunomarkers, but that advanced autolysis may cause a loss of specificity for GFAP, MAP2, and PGP9.5, a loss of intensity of CNPase and OLIG2, and loss of labeling with MAP2 and NeuN. Prolonged fixation affected only NeuN, with mildly decreased intensity.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Encefálicas
/
Doenças do Cão
Limite:
Animals
Idioma:
En
Revista:
J Vet Diagn Invest
Assunto da revista:
MEDICINA VETERINARIA
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Estados Unidos