Strain Differences in Hyperoxia–Related Retinal Degeneration in the Mouse

Abstract

Abstract: : Purpose: Yamada et al. (Am. J. Path. 2001;159:1113–20) have previously shown that the C57BL/6 mouse strain undergoes approximately 50% reduction of ONL thickness after a 2–week exposure to 75% oxygen (hyperoxia–related retinal degeneration) (HRRD). The purpose of our research is to identify the genes and allelic differences contributing to susceptibility to HRRD in the mouse. Methods: C57BL/6J and A/J mouse strains were exposed to hyperoxia (75% O₂) or room air (21% O₂) for two weeks (n=6 for each group). After sacrifice eyes were enucleated and embedded in plastic resin. ONL thickness was measured in one vertical section through the optic disk. Results: We have identified strain specific differential susceptibilities to HRRD. The C57BL/6J strain developed significant retinal degeneration in the inferior posterior region of the fundus. Under identical conditions, the A/J strain did not exhibit statistically significant retinal degeneration. When the B6.A–Chr2 chromosome substitution strain was evaluated, results were equivalent to the C57BL/6J strain. When the B6.A–Chr2 strain was tested, however, results were nearly identical to the A/J strain (no HRRD). Conclusions: These results indicate that within the statistical power of these experiments, no quantitative trait locus (QTL) for HRRD susceptibility is found on chromosome 2. Chromosome 6, however, contains a significant QTL for the same trait.

Keywords: retina • retinal degenerations: hereditary • stress response