Numeric and volumetric changes in Leydig cells during aging of rats.

Purpose: To analyze the effects of aging in rats on the nuclear volume, cytoplasmic volume, and total volume of Leydig cells, as well as their number.

Methods: Seventy-two Wistar rats were divided into six subgroups of 12 rats, which underwent right orchiectomy at 3, 6, 9, 12, 18, and 24 months of age. The weight and volume of the resected testicles were assessed. A stereological study of Leydig cells was conducted, which included measurements of cell number and nuclear, cytoplasmic, and total cell volumes.

Results: The weight and volume of the resected testicles showed reductions with age. Only the subgroup composed of 24-month old rats showed a decrease in the nuclear volume of Leydig cells. Significant reductions in the cytoplasmic volume and total volume of Leydig cells were observed in 18- and 24-month old rats. The number of Leydig cells did not vary significantly with age.

Conclusions: Aging in rats resulted in reduction of the nuclear, cytoplasmic, and total cell volumes of Leydig cells. There was no change in the total number of these cells during aging.