Assessment of Thy-1 mRNA levels as an index of retinal ganglion cell damage.

Abstract

PURPOSE:

Thy-1 is primarily, if not entirely, expressed by the ganglion cells within the retina. This knowledge was used to index ganglion cell death after ischemia and excitotoxicity by studying changes in Thy-1 mRNA levels.

METHODS:

Insults to the rat retina were delivered either by elevation of intraocular pressure for 60 minutes or by intravitreal injection of N-methyl-D-aspartate (NMDA). After a defined period, changes in Thy-1 immunoreactivity and mRNA levels of Thy-1 and NR1 (NMDA receptor subunit) were used to index ganglion cell sensitivity to damage. Opsin mRNA levels were used as an internal control because photoreceptors lack NMDA receptors.

RESULTS:

Retinal Thy-1 immunoreactivity, associated with the ganglion cell and inner plexiform layers, is reduced by ischemia or intravitreal injections of NMDA in a dose-dependent manner. Using a semi-quantitative polymerase chain reaction (reverse transcription-polymerase chain reaction) methodology, the levels of total retinal Thy-1 and NR1 mRNAs were shown to be dramatically reduced after both transient ischemia and intravitreal injection of NMDA. The effect of NMDA was found to be both time- and dose-dependent. In contrast, no change occurred in the levels of opsin mRNA unless high levels of NMDA (200 nmoles) were administered.

CONCLUSIONS:

Ischemia and NMDA-induced excitotoxicity caused retinal ganglion cell destruction, but the photoreceptors were unaffected. Measurement of total retinal Thy-1 mRNA levels provides a useful way of following ganglion cell death especially when combined with immunohistochemical localization of Thy-1. Additionally, the effect on other retinal cell types such as the photoreceptors can be followed in concert using this technique.

• Authors: M S Nash, N N Osborne
• Journal: Investigative ophthalmology & visual science (Invest Ophthalmol Vis Sci) Vol. 40 Issue 6 Pg. 1293-8 (May 1999) ISSN: 0146-0404 [Print] United States
• PMID: 10235569 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Excitatory Amino Acid Agonists
• Neurotoxins
• RNA, Messenger
• Receptors, N-Methyl-D-Aspartate
• Rod Opsins
• Thy-1 Antigens
• N-Methylaspartate

Topics

• Animals
• Excitatory Amino Acid Agonists (pharmacology)
• Immunohistochemistry
• Injections
• Ischemia (metabolism)
• Isomerism
• N-Methylaspartate (pharmacology)
• Neurotoxins (pharmacology)
• RNA, Messenger (metabolism)
• Rats
• Rats, Wistar
• Receptors, N-Methyl-D-Aspartate (metabolism)
• Retinal Ganglion Cells (metabolism, pathology)
• Retinal Vessels
• Reverse Transcriptase Polymerase Chain Reaction
• Rod Opsins (genetics)
• Thy-1 Antigens (genetics, metabolism)
• Vitreous Body