Abstract
Purpose:
Clinically relevant methods for imaging retinal ganglion cell dysfunction and death are needed for improved management of several retinal diseases. In this study, two methods for in vivo imaging of retinal ganglion cell apoptosis were compared using established immunohistochemical methods in conjunction with retinal fluorescence imaging of animal models.
Methods:
Intravitreal injections of staurosporine (SSP), a nonselective protein kinase inhibitor, were used to induce apoptosis in murine retinas. Caspase 3 activatable peptide fluorogenic probes (NucView 488, Biotium Inc.) and Alexa Fluor 488 Annexin V were intravitreally injected in SSP or vehicle treated mice and imaged to detect retinal ganglion cells undergoing apoptosis in vivo. Ex vivo colocalization analysis of imaging probes with cleaved caspase 3 immunostaining was used to confirm specificity.
Results:
Both NucView 488 and Annexin V imaging probes were capable of detecting apoptosing retinal ganglion cells in mice treated with SSP. Colocalization of probes with cleaved caspase 3 was detected. Vehicle-treated eyes did not exhibit fluorescence attributable to either imaging probe.
Conclusions:
Caspase 3 or phosphatidylserine-targeted imaging probes are both relevant reagents for assessment of retinal ganglion cell apoptosis in mice. Fluorescence imaging of retinal ganglion cell apoptosis using targeted imaging probes is promising for enhancing early detection of disease, assessing disease progression, and monitoring therapeutic response.
Keywords: 688 retina •
426 apoptosis/cell death