Gender and chronic stress effects on the neural retina of young and mid-aged Fischer-344 rats

Abstract

Young (5 months) and mid-aged (11 months) male and female Fischer rats were exposed to daily (5 days/week) chronic escapable foot-shock stress for 6 months. Following a subsequent 1-month rest period, by which time the animals were 12 and 18 months old, neural retinas were evaluated histopathologically and morphometrically. A significant reduction in t the thickness of the retina occurred in the mid-aged, as compared to the young animals. A severe age-related loss in photoreceptor cells, particularly in the peripheral zones of the retina, occurred in a pattern resembling that described for aging humans. The effect of stress was to increase photoreceptor loss in a pattern resembling that of age-related cell loss. Stress-associated photoreceptor cell death was observed in males and females of both ages, but was more pronounced and statistically significant for mid-aged males (a five-fold increase in cell loss over females). The results demonstrated that exposure of rats to chronic escapable foot-shock stress exacerbates retinal changes commonly associated with aging and that the deleterious effects of chronic stress exposure were greater in the older age, male group.