Organometric and Biochemical Regularities of Transition to Aging

In a study of male Wistar rats, age-dependent patterns of body mass index (BMI) dynamics and mass coefficient (MC) involution were identified for nine visceral organs with high metabolic activity at young reproductive age (3 months) and low metabolic activity during the transition to aging (12 months). Epididymal fat (EF) was the only organ to demonstrate a progressive increase. Synchronous involution of the thymus and muscles with a progressive accumulation of visceral fat can serve as an integral criterion of early aging that is more informative than assessment of individual organs. A phasic dynamic of antioxidant defense was revealed: a compensatory peak in superoxide dismutase activity at 6 months gives way to its depletion by 12 months, accompanied by a monotonic increase in malondialdehyde. Strong systemic correlations were established, supporting the hypothesis that mitochondria-mediated oxidative stress is a common pathogenetic factor that associates decreased testosterone and involution of lymphoid and muscle tissues. Age-specific MC ranges of ten visceral organs were developed for a period of 3-12 months of age, creating a methodological basis for standardizing gerontological studies and differentiating physiological involution from pathology.