Fine structural alterations in the aging rat pineal gland

Abstract

The pineal glands of 1-28 mo. old male and female rats were examined by EM. With increasing age, the capsule thickness increases; collagen infiltration increases; increased amounts of granular deposits are seen between cells; there is a greater variability in the number of light pinealocytes; pinealocytes with nuclear invaginations and pinealocytes with nuclear inclusions increase in number; more cytoplasmic dense bodies are seen in pinealocytes and gliocytes; the maximum diameter of pinealocyte lipid droplets tends to increase; no definite change is observed in granular endoplasmic reticulum; occasional cells contain reticulated mitochondria, and a few cell processes have an appearance similar to neuroaxonal dystrophy. Besides illustrating age-related changes, the present study apparently proves the existence of pinealocyte nuclear inclusions, suggests the possibility of pineal concretions in the rat, and morphometrically or semi-morphometrically analyzes several structural features not previously quantified.