A "red neuron" (acidophilic or "eosinophilic" neuron) is a pathological finding in
neurons
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
, generally of the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
, indicative of acute neuronal injury and subsequent
apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...
or
necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...
. Acidophilic neurons are often found in the first 12–24 hours after an
ischemic
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...
injury such as a stroke. Since neurons are permanent cells, they are most susceptible to hypoxic injury. The red coloration is due to
pyknosis or degradation of the nucleus and loss of
Nissl bodies which are normally stained blue (
basophilic) on hematoxylin & eosin staining (
H&E stain
Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin–eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diag ...
). This leaves only the degraded proteins which stains red (
eosinophilic). Acidophilic neurons also can be stained with acidic dyes other than eosin (e.g. acid fuchsin and light green yellowish).
References
Pathology
Histology
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