Geroprotectors Melatonin and Epithalon Restore Digestive Enzyme Rhythms in Aging Rats

Aging is often accompanied by a decline in critical physiological functions, including digestive enzyme activity, which is essential for efficient nutrient breakdown and absorption. Furthermore, circadian rhythms, which are biological processes that oscillate over approximately 24 hours and are heavily influenced by environmental light-dark cycles, play a significant role in regulating these digestive processes. The precise impact of disrupted lighting conditions on age-related changes in digestive function, and the potential for geroprotectors (compounds that counteract aging processes) to intervene, remains an important but underexplored area, especially regarding their ability to normalize enzyme dynamics under environmental stress.

Under standard illumination, the study observed a characteristic age-related pattern: both pepsin activity and the total proteolytic activity in the stomach and pancreas significantly increased by the age of 12 months, followed by a subsequent decrease in older animals. However, exposure to constant lighting and, to a lesser extent, natural lighting, profoundly disturbed these normal age dynamics of proteolytic digestive enzyme activity. This disruption suggests that altered light environments can negatively impact the natural progression of digestive function with age. Administration of melatonin and epithalon to rats exposed to constant lighting remarkably restored the age dynamics of pepsin activity, effectively mitigating the negative effects of continuous light exposure and normalizing the enzyme's age-related trajectory. Interestingly, these geroprotectors had little effect on the total proteolytic activity, indicating a more targeted or specific impact on certain enzymes like pepsin rather than a broad enhancement of all proteolytic functions.