Caspase-3-Dependent and -Independent Apoptosis in Focal Brain Ischemia

Vladimir V Didenko,Denise J Boudreaux,David S Baskin,Candace L Minchew,Marsha A Widmayer,Hop Ngo

doi:10.1007/bf03402015

Vladimir V Didenko, Denise J Boudreaux + Show 4 more

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https://doi.org/10.1007/bf03402015

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Journal: Molecular Medicine	Publication Date: Jul 1, 2002
Citations: 63	License type: cc-by

Affiliation: Baylor College of Medicine

Abstract

Although extensive caspase-3 activation has been demonstrated in experimental brain ischemia produced in neonatal rat, the role this caspase plays in the focal ischemia of adult brain is not clear, as the levels of caspase-3 in adult rat brain are extremely low. This raises the question whether caspase-3 synthesis and activation are essential for execution of the apoptotic program and DNA fragmentation in permanent brain ischemia, a condition that impairs cellular protein synthesis. Rat middle cerebral artery was permanently occluded and histochemical detection of procaspase-3, active caspase-3 and DFF 40/CAD and apoptotic morphology analysis were performed at 6, 24, 48, and 72 hours after occlusion. Necrosis and two types of programmed cell death (PCD) are identified in this study of permanent focal brain ischemia. The first type of PCD is represented by active caspase-3 and DFF 40/CAD-positive cells. The second type of PCD is represented by caspase-3 and DFF40/CAD negative cells, which display morphological signs of apoptosis-like PCD: namely, nuclear chromatin condensation in lump masses and apoptotic body formation. The cells of the first type have a maximum number noted after 24 hours of ischemia. The cells of the second type are primarily seen after 48 and 72 hours of ischemia. Necrotic cells, which are also detected in the stroke, are caspase-3 negative, and have swollen nuclei, without chromatin condensation and apoptotic body formation. Our results indicate that in permanent brain ischemia in adult rats, PCD processes occur differently in various parts of ischemic zone. In conditions of severe energy depletion, the reactions of cellular disassembly and packaging into apoptotic bodies are accomplished without either caspase-3 expression or the activation of caspase-3-dependent deoxyribonuclease.

Highlights

Apoptosis is an orderly process of cellular suicide
Using immunohistochemical staining for active caspase-3, we detected the cells with active caspase-3 at our earliest time point of 6 hours after the onset of ischemia
Extensive and uniform caspase-3 activation throughout the ischemic zone was demonstrated after brain ischemia in neonatal rat [9], an adult rat brain has very low initial levels of procaspase-3, and additional synthesis would be required to achieve the levels similar to those in a neonatal rat brain [10,11]

Summary

Introduction

Apoptosis is an orderly process of cellular suicide It is usually initiated by the activation of caspases, and produces DNA fragmentation and cell disassembly. Extensive caspase-3 activation has been demonstrated in experimental brain ischemia produced in neonatal rat, the role this caspase plays in the focal ischemia of adult brain is not clear, as the levels of caspase-3 in adult rat brain are extremely low This raises the question whether caspase-3 synthesis and activation are essential for execution of the apoptotic program and DNA fragmentation in permanent brain ischemia, a condition that impairs cellular protein synthesis. The second type of PCD is represented by caspase-3 and DFF40/CAD negative cells, which display morphological signs of apoptosis-like PCD: namely, nuclear chromatin condensation in lump masses and apoptotic body formation. In conditions of severe energy depletion, the reactions of cellular disassembly and packaging into apoptotic bodies are accomplished without either caspase-3 expression or the activation of caspase-3dependent deoxyribonuclease

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Conclusion