Radiation-induced crypt intestinal epithelial cell apoptosis in vivo involves both caspase-3-dependent and -independent pathways.
Caspases play a major role in virtually all forms of apoptosis. Radiation is well known to induce apoptosis of crypt intestinal epithelial cells (IEC). Here, we examined the role of caspase-3 in radiation-induced IEC apoptosis. We demonstrate that while caspase-3 is present in IEC and activated upon irradiation, IEC in caspase-3-deficient mice partially underwent radiation-induced apoptosis. Typical morphological changes of IEC undergoing radiation-induced apoptosis (ie, blebbing, shrinkage, and nuclear condensation) can occur independently of caspase-3; however DNA fragmentation, as analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, is mostly, but not entirely, caspase-3-dependent. Overall, these results demonstrate that radiation-induced crypt IEC apoptosis has both caspase-3-independent and -dependent components.
Inagaki-Ohara
Kyoko
K
Section of Gastroenterology, Department of Medicine, Northwestern University Medical School, 10-541 Searle Building, 303 E. Chicago, Chicago, Illinois 60611, USA.
Takamura
Noriaki
N
Yada
Shinichiro
S
Alnadjim
Ziad
Z
Liu
Erding
E
Yu
Xiaohong
X
Yoshida
Hiroki
H
Lin
Tesu
T
D000818:Animals; D017209:Apoptosis / Q000502:physiology* / Q000528:radiation effects*; D053148:Caspase 3; D020169:Caspases / Q000502:physiology*; D053938:DNA Fragmentation / Q000502:physiology; D004847:Epithelial Cells / Q000502:physiology*; D005720:Gamma Rays; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases