A. Rink et al., EVIDENCE OF APOPTOTIC CELL-DEATH AFTER EXPERIMENTAL TRAUMATIC BRAIN INJURY IN THE RAT, The American journal of pathology, 147(6), 1995, pp. 1575-1583
Apoptosis plays an important role in many developmental and pathologic
al processes of the central nervous system. However, the role of apopt
osis in traumatic brain injury has not been determined. Using the term
inal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine t
riphosphate nick end labeling (TUNEL) method, we detected many cells w
ith extensive DNA fragmentation in different regions of the brains of
rats subjected to experimental traumatic brain injury. Two type of TUN
EL-positive cells were demonstrated by light and electron microscopy,
including type I cells that displayed morphological feature of necroti
c cell death and type II cells that displayed morphological features o
f classic apoptotic cell death. TUNEL-positive cells were detectable f
or up to 72 hours after the initial injury. Gel electrophoresis of DNA
extracted from affected areas of the injured brain containing both ty
pe I and II cells revealed only internucleosomal fragmentation at 185-
bp intervals, a feature originally described in apoptotic cell death.
These data suggest that apoptosis, in addition to necrotic cell death,
occurs after traumatic brain injury, and that internucleosomal fragme
ntation of DNA may be associated with certain types of necrotic cell d
eath.