Protective effect of thioredoxins 1 and 2 in retinal ganglion cells after optic nerve transection and oxidative stress.
OBJECTIVE
Oxidative stress has been implicated in retinal ganglion cell (RGC) death pathways after optic nerve transection (ONT) and during glaucomatous neuropathy. The authors investigated the expression and cell-protective roles of thioredoxins (cytosolic Trx1 and mitochondrial Trx2), important regulators of the cellular redox state, on RGCs after ONT and pharmacologic oxidative stress induction.


METHODS
ONT was performed on adult Wistar rats. Trx1 and Trx2 quantitative and spatial expression were examined with Western blot and immunohistochemistry, respectively. Electroporation and calcium phosphate-mediated procedures were used to deliver Trx1 and Trx2 expression constructs to RGCs in vivo and to cultured RGC-5 cells, respectively. Cell-protective effects of Trx1 and Trx2 overexpression on RGCs after ONT and on RGC-5 cells treated with glutamate/buthionine sulfoximine (BSO) were determined by RGC density analysis and cell viability assay, respectively.


RESULTS
Upregulation of Trx1 and Trx2 was observed in RGCs at different times after ONT and in RGC-5 cells after glutamate/BSO treatment. Trx1 and Trx2 overexpression in RGC-5 cells increased their survival rate by approximately twofold and threefold 24 and 48 hours after glutamate/BSO treatment, respectively. A neuroprotective effect of Trx1 and Trx2 overexpression on RGCs was also observed in vivo; the survival rate of RGCs was increased by 35% and 135%, respectively, 1 and 2 weeks after ONT.


CONCLUSIONS
These findings provide evidence for in vitro and in vivo cell-protective effects of Trx1 and Trx2 on RGCs against oxidative stress-induced neurodegeneration.
Munemasa
Yasunari
Y
Jules Stein Eye Institute, University of California at Los Angeles, Los Angeles, California 90095, USA.
Kim
Seok Hwan
SH
Ahn
Jae Hong
JH
Kwong
Jacky M K
JM
Caprioli
Joseph
J
Piri
Natik
N
D000818:Animals; D019771:Axotomy; D015153:Blotting, Western; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002452:Cell Count; D002470:Cell Survival; D018274:Electroporation; D005786:Gene Expression Regulation / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology; D007150:Immunohistochemistry; D020221:Optic Nerve Injuries / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism*; D013879:Thioredoxins / Q000502:physiology*; D014162:Transfection; D015854:Up-Regulation
C495697:Txn1 protein, rat; C516113:Txn2 protein, rat; D018698:Glutamic Acid; D019328:Buthionine Sulfoximine; D013879:Thioredoxins