Pineal Gland Factors Boost Immune Function in Aging Mice In Vitro

The thymus gland is crucial for immune system development, producing T-cells that fight infections. As organisms age, thymus function naturally declines, leading to a weakened immune response, a phenomenon known as immunosenescence. This decline is a major contributor to increased susceptibility to infections and diseases in the elderly. Researchers have long sought ways to counteract this age-related immune decline, and the pineal gland, known for producing hormones like melatonin, has been implicated in immune regulation. This study specifically investigates how bioactive factors from the pineal gland, including peptides, influence thymus function and immune cell composition in adult and old mice.

The study revealed that Epithalamin, Epithalon, and melatonin all appreciably increased the titer of thymic serum factor in the supernatant of thymus stroma cultures, regardless of the mice's age. This suggests a direct stimulatory effect on thymus function. Furthermore, these factors led to a significant increase in the percentage of CD4+ cells (a type of helper T-lymphocyte crucial for coordinating immune responses) in the bone marrow suspension from old animals. Conversely, the percentage of CD8+ lymphocytes (cytotoxic T-cells that kill infected cells) decreased after incubation of splenic cells from old mice with melatonin. The percentage of bone marrow fibroblast precursor cells from both adult and old mice did not show any appreciable change after incubation with the preparations. The most important finding is that Epithalamin, Epithalon, and melatonin consistently increased thymic serum factor, indicating a direct and positive influence on thymus activity across different age groups, particularly beneficial for the aging immune system.