Caspase-3 is activated following axotomy of neonatal facial motoneurons and caspase-3 gene deletion delays axotomy-induced cell death in rodents

Eur J Neurosci. 2000 Oct;12(10):3469-80. doi: 10.1046/j.1460-9568.2000.00241.x.


In this report, we examined the possible functions of the cell death protease, caspase-3, in the axotomy-induced apoptosis of facial motoneurons in newborn rodents. Using in situ hybridization and Western blot, we found higher levels of caspase-3 mRNA and pro-caspase-3 protein expression in motoneurons of neonatal and 2-week-old rats than adult rats. Following facial motoneuron axotomy, caspase-3 mRNA and protein expression increased in motoneurons of both neonatal and adult rats. However, using an antibody directed to the activated form of the caspase-3 protease, we found that catalytically active caspase-3 was present only in axotomized neonatal motoneurons. As motoneurons in neonatal but not adult rodents are susceptible to axotomy-induced apoptosis, we hypothesized that caspase-3 may play a role in their demise. To determine the necessity of caspase-3 activation in axotomy-induced apoptosis, we counted the number of surviving motoneurons at 4 and 7 days following axotomy in wild type mice and caspase-3 gene-deleted mice. There were nearly three times more surviving motoneurons in caspase-3 gene-deleted mice than in wild type mice at both 4 days (mean 1074 vs. 464, P<0.005) and 7 days (mean 469 vs. 190, P<0.005) following injury, indicating a slower rate of death. Examination of the dying motoneurons using TUNEL staining (for fragmented DNA) and bisbenzimide staining (for nuclear morphology) revealed incomplete nuclear condensation in caspase-3-deficient motoneurons. These results demonstrate that caspase-3 activation plays important roles in the rapid demise of axotomized neonatal motoneurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Animals, Newborn
  • Apoptosis / genetics*
  • Axotomy
  • Caspase 3
  • Caspases / genetics
  • Caspases / metabolism*
  • Facial Nerve / physiopathology*
  • Facial Nerve / surgery
  • Female
  • Fetus
  • Gene Deletion
  • Male
  • Mice
  • Mice, Knockout
  • Motor Neurons / metabolism*
  • Motor Neurons / pathology
  • Nerve Degeneration / enzymology*
  • Nerve Degeneration / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors


  • RNA, Messenger
  • Casp3 protein, mouse
  • Casp3 protein, rat
  • Caspase 3
  • Caspases