Quantitative analysis of the renal aging in rats. Stereological study

Abstract

Brazil. Scientific, intellectual, conception and design of the study; analysis and interpretation of data; statistics analysis; critical revision. ABSTRACT PURPOSE:To evaluate the renal function and the renal histological alterations through the stereology and morphometrics in rats submitted to the natural process of aging. METHODS:Seventy two Wistar rats, divided in six groups. Each group was sacrificed in a different age: 3, 6, 9, 12, 18 and 24 months.It was performed right nephrectomy, stereological and morphometric analysis of the renal tissue (renal volume and weight, density of volume (Vv [glom] ) and numerical density (Nv [glom] ) of the renal glomeruli and average glomerular volume (Vol [glom] )) and also it was evaluated the renal function for the dosage of serum creatinine and urea. RESULTS:There was significant decrease of the renal function in the oldest rats. The renal volume presented gradual increase during the development of the rats with the biggest values registered in the group of animals at 12 months of age and significant progressive decrease in older animals. Vv [glom] presented statistically significant gradual reduction between the groups and the Nv [glom] also decreased significantly. CONCLUSIONS:The renal function proved to be inferior in senile rats when compared to the young rats. The morphometric and stereological analysis evidenced renal atrophy, gradual reduction of the volume density and numerical density of the renal glomeruli associated to the aging process.Key words: Aging. Kidney. Histology. Rats.Quantitative analysis of the renal aging in rats. Stereological study Acta

Age-related changes of malondialdehyde, body weight and organ weight in male mice

“…The increase in the volume of the kidneys in older rats was apparently also marked by a decrease in renal function. (18) In contrast to the study results of Melchioretto et al (18) who state that increases in the volume of the kidneys are observable in rats from the age of 12 months, our study showed a peak increase in the weight of the kidneys occurring at the ages of 8 months (32 weeks) and 12 months (48 weeks). This may be due to the differences in experimental animals used.…”

“…(26) The results of our study showed increases in organ weight of the kidneys, liver, spleen and testes with increasing age. The increases in the weight of the kidneys, liver, and spleen in our study are in line with those of Caglar et al, (13) Kim et al (14) and Melchioretto et al (18) , which are the results of autopsies on humans. The increases in the weight of the kidneys, liver, and spleen occurred concomitantly with increases in individual body weight and body mass index (BMI).…”

“…The increases in the weight of the kidneys, liver, and spleen occurred concomitantly with increases in individual body weight and body mass index (BMI). (13,14,18) The spleen is subject to growth up to the age of 25 years in humans. (13) In line with abovementioned studies, the increased weight of the spleen in our study could be observed starting from the age of 40 weeks.…”

“…(13)(14)(15) In experimental animals, studies on changes in organ mass are aimed at determining the agerelated developmental pattern of an organ and also the underlying mechanism of the aging process. (16)(17)(18)(19) Therefore, studies on experimental animals are far more feasible to be performed by investigators as compared with studies on humans.…”

“…A study on Wistar rats showed that the volume of the kidneys increases up to the age of 12 months and decreases afterwards. (18) The brain experiences a rapid increase in volume at the age of less than 20 weeks and thereafter the development becomes static. (19) In humans, there is a negative correlation between aging and the weight of the brain, kidneys, liver, and spleen.…”