Neuroprotective Effects of Tempol on Retinal Ganglion
Cells in a Partial Optic Nerve Crush Rat Model with
and Without Iron Load.
Thaler S, Fiedorowicz M, Rejdak R, Choragiewicz TJ,
Sulejczak D, Zarnowski T, Zrenner E, Grieb P, Schuettauf F.

Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.

Iron overload can contribute to oxidative stress in many tissues.
We studied the effects of pre-treatment with iron dextran on RGC
loss in a calibrated partial optic nerve crush (PONC) model in rats,
along with the protection offered by tempol
(4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl, a membrane-
permeable
superoxide dismutase mimetic and free-radical scavenger), in the same
experimental paradigm.
A total of 40 rats in 6 groups of 5-8 animals each underwent PONC in
one eye and sham crush in the other.
Animals were pre-treated with a single iron dextran load 24hours prior
to
PONC, and treated with Tempol 6hours before and then once daily after
PONC.
Control animals were treated with PBS. RGC were retrogradely labeled
with a fluorescent marker; all data are expressed in percent of the
RGC
count in the respective sham-treated eye.
Immunohistochemistry was performed to visualize 3-nitrotyrosine, a
marker of nitroxidative stress.
PONC without iron pretreatment resulted in the survival of only 31.4%
of labeled RGC after 7 days.
Even fewer RGC (12.7%) survived after PONC with iron pretreatment.
However, tempol in doses of 20mg/kg of body weight (BW) significantly
attenuated this effect when given as described above; in the group
without
iron pretreatment the number of surviving RGC doubled from 31.4% to
62.1%.
In the group with iron pretreatment the survival rate of RGC increased
even
more pronouncedly, from 12.7% without tempol to 46.2% with tempol.
Tempol in doses of 1mg/kg BW and 5mg/kg BW showed no significant
rescue of RGC.
Immunostaining showed nitrotyrosine-positive RGCs in PONC but not in
sham-treated eyes and an increase in positive cells after iron load.
Tempol treatment reduced nitrotyrosine staining in both the iron and
non-iron
groups.
Our results demonstrate that PONC results in significantly greater
RGC
damage when iron pretreatment is performed, and that the compound
tempol
may provide additional protection for RGC in cases of neuronal damage
both
with and without prior iron treatment.

PMID: 19883642

Who loves ya.
Tom

Jesus Was A Vegetarian!
http://tinyurl.com/2r2nkh

Man Is A Herbivore!
http://tinyurl.com/a3cc3

DEAD PEOPLE WALKING
http://tinyurl.com/zk9fk

Only if the "pretreatment" involved adding an iron sugar mixture to one
of your crushed eyeballs, after it was crushed.

We are getting desperate now.