Apoptotic retinal neuronal death by ischemia-reperfusion is executed by two distinct caspase family proteases.

Abstract

PURPOSE:

To evaluate possible roles of caspase-1 and caspase-3 in retinal ischemia-reperfusion injury.

METHODS:

Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mm Hg for 60 minutes. Expression of caspase-1 and caspase-3 was studied at the mRNA and protein levels using immunohistochemical staining, western blot analysis, semiquantitative reverse transcription-polymerase chain reaction, and assay of the enzymatic activities. Apoptotic retinal neurons were detected by the TdT-dUTP terminal nick-end labeling (TUNEL) method. To study the roles of the caspases in retinal ischemia-reperfusion injury, an inhibitor of caspase-1, acetyl-tyrosyl-valyl-alanyl-aspart-1-al (Ac-YVAD-CHO; total dose, 10(-7) moles) and that of caspase-3, acetyl-aspartyl-glutamylvalyl-aspart-1-al (Ac-DEVD-CHO; total dose, 10(-7) moles) was injected intravitreally and the number of TUNEL-positive cells was compared with the number in sections not treated with the inhibitors.

RESULTS:

In the inner nuclear layer (INL), caspase-3-like immunoreactivity was predominantly detected, whereas caspase-1-like immunoreactivity was more predominant in the outer nuclear layer (ONL). Expression of caspase-1 and -3 was upregulated at the protein and gene levels 24 hours after reperfusion. Intravitreal injection of Ac-DEVD-CHO decreased the number of TUNEL-positive cells more significantly in the INL than in the ONL (P < 0.01) at 24 hours, whereas, intravitreal injection of Ac-YVAD-CHO was more effective in decreasing the number in the ONL (P < 0.05).

CONCLUSIONS:

These findings suggest a possibility that cell-type-specific activation of caspases takes place in retinal ischemia-reperfusion injury, and such caspase may induce retinal neuronal cell death.

• Authors: N Katai, N Yoshimura
• Journal: Investigative ophthalmology & visual science (Invest Ophthalmol Vis Sci) Vol. 40 Issue 11 Pg. 2697-705 (Oct 1999) ISSN: 0146-0404 [Print] United States
• PMID: 10509668 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Caspase Inhibitors
• Cysteine Proteinase Inhibitors
• DNA Primers
• Oligopeptides
• acetyl-aspartyl-glutamyl-valyl-aspartal
• L 709049
• Casp3 protein, rat
• Caspase 3
• Caspases
• Caspase 1

Topics

• Animals
• Apoptosis
• Blotting, Western
• Caspase 1 (genetics, metabolism)
• Caspase 3
• Caspase Inhibitors
• Caspases (genetics, metabolism)
• Cysteine Proteinase Inhibitors (pharmacology)
• DNA Primers (chemistry)
• Fluorescent Antibody Technique, Indirect
• Gene Expression
• In Situ Nick-End Labeling
• Male
• Neurons, Afferent (enzymology, pathology)
• Oligopeptides (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Reperfusion Injury (enzymology, pathology)
• Retina (enzymology, pathology)
• Reverse Transcriptase Polymerase Chain Reaction
• Up-Regulation