Quench-assisted MRI measurement in vivo of outer retina oxidative stress. (
A) 1/T1 MRI profiles in vivo comparing one dark-adapted control group, doxycycline-treated
Sod2flox/flox mice lacking the cre transgene (“RPEKO controls,”
green, n = 7), doxycycline-treated
Sod2flox/flox mice expressing cre recombinase (“RPEKO,”
blue,
n = 5), and RPEKO mice treated with antioxidant (AO) (“RPEKO+AO,”
red,
n = 5). (
B) 1/T1 MRI profiles in vivo comparing another dark-adapted control group, wild-type mice (“B6,”
black,
n = 20), doxycycline-treated
Sod2flox/flox mice expressing cre recombinase (“RPEKO,”
blue,
n = 5), and RPEKO mice treated with AO (“RPEKO+AO,”
red,
n = 5). In both graphs, representative OCT images (
above) illustrate laminar spacing within the retina; layer assignments are presented.
66 Dashed vertical lines map outer plexiform layer (OPL) (42%) and retina/choroid boundary (100%) onto MRI profiles (
below); MRI insert shows regions studied (
white boxes); visual inspection of each groups' MRI does not allow for easy appreciation of differences in the derived parameter 1/T1 and so only a representative image is presented. *Retinal depth range with significant difference (
P < 0.05). Adjusted 1/T1 data at each depth used factors that normalize same-day B6 controls to a B6 control reference data set. GCL, ganglion cell layer; INL, inner nuclear layer; IPL, inner plexiform layer; IS, rod inner segment layer; OLM, outer limiting membrane; ONL, outer nuclear layer; OPL, outer plexiform layer; OS, rod outer segment layer.