Serdar Balcı

Injury in central nervous system

Serdar BALCI, MD



Features of Neuronal Injury

Shrinkage of the cell body, pyknosis of the nucleus, disappearance of the nucleolus, and loss of Nissl substance, with intense eosinophilia of the cytoplasm (“red neurons”)

**Nucleus assumes the angulated shape of the shrunken cell body **

Acute hypoxic-ischemic injury in cerebral cortex, where the individual cell bodies are shrunken, along with the nuclei. They also are prominently stained by eosin (“red neurons”).

Robbins Basic Pathology

Injured axons undergo swelling and show disruption of axonal transport

Swellings (spheroids) can be recognized on H&E stains and can be highlighted by silver staining or immunohistochemistry.

Axonal spheroids are visible as bulbous swellings at points of disruption, or altered axonal transport.

Robbins Basic Pathology

Axonal injury

-leads to cell body enlargement and rounding

-peripheral displacement of the nucleus

-enlargement of the nucleolus

-peripheral dispersion of Nissl substance (central chromatolysis)

C: With axonal injury there can be swelling of the cell body and peripheral dispersal of the Nissl substance, termed chromatolysis.

Robbins Basic Pathology

Other diseases also cause changes in neurons

Astrocytes in Injury and Repair

Robbins and Cotran Pathologic Basis of Disease


Participate in healing after brain injury to a limited extent

Except in penetrating brain trauma or around abscesses

Fibrillary astrocytes

Long-standing gliosis

Cytoplasm of reactive astrocytes shrinks in size

Cellular processes become more tightly interwoven

Rosenthal fibers

Thick, elongated, brightly eosinophilic protein aggregates found in astrocytic processes in chronic gliosis and in some low-grade gliomas


Microglial cells

Bone-marrow–derived cells

Function as the resident phagocytes of the CNS

Activated by tissue injury, infection, or trauma

Proliferate and become more prominent histologically

Ependymal cells