Abstract
Purpose:
The pathogenic pathways triggered by blast injury to the eye and biomarkers that reflect the activation of these pathways are largely unknown. The present study is the initial attempt to define potential biomarkers that reflect the severity of the retinal injury.
Methods:
Blast injuries to the eye were produced by a paintball gun fitted with a shortened and narrowed barrel and an integrated pressure regulator. The mice were deeply anesthetized and secured in a PVC pipe. A 45-psi overpressure wave was delivered selectively to the eye of C57BL/6 mice and DBA/2J mice. The animals were then sacrificed at 2 or 5 days after the blast injury. To aid in our initial survey of potential biomarkers of retinal injury, we examined our Optic Nerve Crush Microarray Dataset and compared it to our Normal Retinal Microarray Dataset in GeneNetwork.org. This work led to six potential biomarkers for blast injury, Gfap, Iba1, C1q, Aqp4, Sox11 and Hsp25. One set of retinas were removed and stained by indirect immunohistochemical methods to assess the distribution and intensity of the staining compared to uninjured control retinas. For a second set of retinas, the animals were anesthetized; the retinas were removed and placed in sample buffer. The level of protein expression was determined by semi-quantitative immunoblot methods.
Results:
Immunostaining sections of retina revealed that two of the markers, SOX11 and HSP25, were upregulated in the neurons of the inner retina following blast. Both SOX11 and HSP25 labeled cells in the ganglion cell layer and the inner nuclear layer. In the ganglion cell layer SOX11 labeled approximately 90% of the cells, indicating that it was labeling most ganglion cells and displaced amacrine cells. Furthermore, amacrine cells in the inner nuclear layer were labeled by SOX11. The intensity of staining increased dramatically after blast injury and on immunoblots there was approximately a 2-fold increase in the intensity of the SOX11 band. A similar pattern of staining was observed with HSP25. The increased staining after blast injury did not appear to be as dramatic as it was for SOX11. On immunoblots, there was also an observed increase in the intensity of the HSP25 band following injury.
Conclusions:
SOX11 and HSP25 are markers for blast injury to the retina, labeling both retinal ganglion cells and amacrine cells. The better of the two markers appears to be SOX11.
Keywords: 742 trauma •
637 pathology: experimental •
496 detection