title: Hyperbaric oxygen preconditioning promotes survival of retinal ganglion cells in a rat model of optic nerve crush.
abstract: In this study we tested the hypothesis that hyperbaric oxygen preconditioning (HBO-PC) reduces retinal neuronal death due to optic nerve crush (ONC). Adult male Sprague-Dawley rats were subjected to ONC accompanied by a contralateral sham operation. HBO-PC was conducted four times by giving 100% oxygen at 2.5 atmospheres absolute (ATA) for 1 h every 12 h for 2 days prior to ONC. The rats were euthanized at 1 or 2 weeks after ONC. Retinal ganglion cell (RGC) density was counted by hematoxylin and eosin (H&E) staining of the retina and retrograde labeling with FluoroGold application to the superior colliculus. Visual function was assessed by flash visual evoked potentials (FVEP). TUNEL straining and caspase-3 and caspase-9 activity in the retinas were assessed. The RGC density in the retinas of ONC HBO-PC-treated rats was significantly higher than that of the corresponding ONC-only rats (the survival rate was 67.2% versus 49.7% by H&E staining, and 60.3% versus 28.9% by retrograde labeling with FluoroGold, respectively; p < 0.01) at 2 weeks after ONC. FVEP measurements indicated a significantly better preserved latency and amplitude of the P1 wave in the ONC HBO-PC-treated rats than the ONC-only rats (92 +/- 7 msec, 21 +/- 3 microv in the sham-operated group, 117 +/- 12 msec, 14 +/- 2 microv in the HBO-PC-treated group, and 169 +/- 15 msec, 7 +/- 1 microv in the corresponding ONC group; p < 0.01). TUNEL assays showed fewer apoptotic cells in the HBO-PC-treated group, accompanied by the suppression of caspase-3 and caspase-9 activity. These results demonstrate that HBO-PC appears to be neuroprotective against ONC insult via inhibition of neuronal apoptosis pathways.
authors.affiliation: Department of Ophthalmology, Changhai Hospital, Shanghai, China.
authors.forename: Ruobing
authors.initials: R
authors.lastname: Wang
authors.forename: Jiajun
authors.initials: J
authors.lastname: Xu
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Xie
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Kang
authors.forename: Xuejun
authors.initials: X
authors.lastname: Sun
authors.forename: Na
authors.initials: N
authors.lastname: Chen
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.forename: Jiajun
authors.initials: J
authors.lastname: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002470:Cell Survival / Q000502:physiology; D019610:Cytoprotection / Q000502:physiology; D004195:Disease Models, Animal; D006931:Hyperbaric Oxygenation; D020287:In Situ Nick-End Labeling; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D009410:Nerve Degeneration / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D056347:Neuroanatomical Tract-Tracing Techniques; D009900:Optic Nerve / Q000166:cytology / Q000502:physiology; D020221:Optic Nerve Injuries / Q000150:complications*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012162:Retinal Degeneration / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000502:physiology*; D013194:Staining and Labeling; D013266:Stilbamidines; D014795:Visual Pathways / Q000166:cytology / Q000293:injuries / Q000502:physiology
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D013266:Stilbamidines; D053148:Caspase 3; D053453:Caspase 9