Resistance of photoreceptors in the C57BL/6-c2J, C57BL/6J, and BALB/cJ mouse strains to oxygen stress: evidence of an oxygen phenotype.
OBJECTIVE
To assess the vulnerability of retinal photoreceptors in the BALB/cJ, C57BL/6J, and C57BL/6-c2J (c2J) mouse strains to hypoxic and hyperoxic stress.


METHODS
Mice were raised in dim cyclic light. Pups aged postnatal day 7 (P7) were exposed to hypoxia (11-12% oxygen) for periods up to 23 days. Adult mice were exposed to either hypoxia (12% oxygen) or to hyperoxia (75% oxygen) for up to 2 weeks. Using the TUNEL (terminal dUTP-mediated nick end labeling) technique retinas were examined for cell death.


RESULTS
In juvenile mice, hypoxia induced a robust increase in photoreceptor death in the C57BL/6J strain and a weaker increase in the C57BL/6-c2J strains. In the adult, hypoxia was associated with a small reduction in photoreceptor death in the C57BL/6-c2J strains. Hyperoxia caused substantial photoreceptor death in both the C57BL/6-c2J and C57BL/6J strains. The BALB/cJ strain was more resistant to oxygen stress than the C57BL strains.


CONCLUSIONS
The difference in oxygen vulnerability between C57BL/6J and BALB/c strains may provide a useful starting point for the analysis of genetic regulation of this vulnerability. The resistance of the C57BL/6-c2J substrains to hypoxia may reflect their degenerative status.
Walsh
Natalie
N
Department of Anatomy and Histology, Institute for Biomedical Research, University of Sydney, Sydney, Australia.
Bravo-Nuevo
Arturo
A
Geller
Scott
S
Stone
Jonathan
J
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D018496:Hyperoxia / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress; D010100:Oxygen / Q000633:toxicity*; D010641:Phenotype; D010786:Photoreceptor Cells / Q000187:drug effects* / Q000528:radiation effects; D012162:Retinal Degeneration / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*
D010100:Oxygen