Immediate and Late Effects of Stress on Kidneys of Prepubertal and Adult Rats.

BACKGROUND/AIMS: Stress had been related to physiological and morphological alterations in different organs, however kidney morphology and function after stress conditions are not well-known. To evaluate the effects of chronic stress on renal morphology in prepubertal and adult rats, and to investigate if the effects of induced stress remain stable or worsen following removal of the stress stimuli. METHODS: Forty prepubertal rats (4 weeks old) and thirty six adult rats (10 weeks old) were used. Each age group was divided a into control group and a stressed group. Stressed animals were restrained in rigid tubes 2 hours per day for 6 weeks. Animals were euthanized 24 hours after the last stress stimulus for immediate evaluation (50% of the groups), and 6 weeks after the last stress stimulus for late evaluation (50% of the groups). Kidney weight and volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted glomerular volume, and number of glomeruli per kidney were evaluated using the Image J software. RESULTS: Prepubertal stressed animals showed reduced kidney weight and volume, and increased cortical-medullar ratio in comparison to its control group when evaluated immediately. Furthermore, stressed prepubertal and adult animals evaluated immediately had reduced glomerular volumetric density. Most importantly, all stressed groups exhibited reduced number of glomeruli per kidney. Other analyzed parameters did not difeer significantly the groups. CONCLUSION: Chronic stress induced before and after puberty led to irreversible glomerular loss, however, renal impairment was interrupted by removal of the stress stimuli.