Figure 1. Optic nerve crush decreased
number of retinal ganglion cells (RGCs), thy-1 protein, and mRNA
levels. The mean number of RGCs labeled retrogradely from superior
colliculus was 2090±85/mm2 in sham rats without any
treatment (A), which decreased to 1091±78 (47% loss, B)
and 497±87/mm2 (76% loss, C) on day 7 and 14,
respectively. Thy-1 expressed by retinal ganglion cells is widely used
as marker for RGC stress and was shown to be reduced following optic
nerve crush. Following retinal injuries with optic nerve crush, retinas
were dissected and plasma membrane proteins were isolated or total RNA
was isolated and transcribed into cDNA. Thirty microgram protein was
loaded into each lane. D: Immunoreactive bands for thy-1 and
β-tubulin at 2, 7, and 14 days following crush showing a significant
reduction in thy-1 protein levels at 7 and 14 day but not at 2 days
(94±18%, 33±6%, 24±7% at 2, 7, and 14 day, respectively, n=7).
Densitometric quantification is shown in E. Data are expressed
as a ratio of the control value and each measurement represents
mean±SEM *Denotes statistical significance of thy-1 protein levels in
optic nerve crushed retinas versus sham (p<0.005) as determined by
one-way ANOVA and Tukey multiple comparison test. Optic nerve crush
also decreased thy-1 transcripts significantly (58±7%, 6±2%, at 2 and 7
day, respectively, % p<0.001 versus sham, n=8), as determined by
quantitative real-time PCR (E). Thy1- mRNA at 2-weeks was below
detection levels and considered zero. Gene expression data of thy-1 is
calculated after normalizing with β-actin. **Denote significant
differences compared with sham-retinas at p<0.05. Abbreviations:
sham eye (C), and crushed (R).