Overview Rhabditid nematodes, exemplified by Caenorhabditis elegans (C. elegans), are a crucial model system for studying aging. These nematodes have a simple anatomy, transparent bodies, and a short, well-defined lifespan, allowing researchers to observe aging processes in real-time and at cellular resolution. Lifespan and Development C. elegans typically has a lifespan of about 2-3 weeks under laboratory conditions. The life cycle consists of an embryonic stage, four larval stages (L1-L4), and adulthood. Aging research primarily focuses on the adult stage, which can be divided into early, mid, and late adulthood, characterized by distinct physiological and molecular changes. Genetic Regulation of Aging Several genes and pathways are known to regulate aging in rhabditid nematodes: Insulin/IGF-1 Signaling (IIS) Pathway: The DAF-2/insulin receptor and DAF-16/FOXO transcription factor are central to this pathway. Mutations that reduce IIS activity increase lifespan. Target of Rapamycin (TOR) Pathway: This nutrient-sensing pathway influences growth and longevity, with reduced TOR signaling being associated with increased lifespan. Mitochondrial Function: Mitochondrial integrity and function are crucial for longevity. Mutations affecting mitochondrial electron transport chain components can extend lifespan. Stress Response Pathways: Heat shock proteins, oxidative stress response, and other stress-related pathways play significant roles in longevity. Cellular and Molecular Mechanisms Proteostasis: Maintenance of protein homeostasis, including proper protein folding, degradation, and aggregation prevention, is vital for longevity. Decline in proteostasis is a hallmark of aging in nematodes. Autophagy: This cellular process for degrading and recycling cellular components is essential for lifespan extension. Enhanced autophagy correlates with increased longevity. DNA Damage and Repair: Efficient DNA repair mechanisms are associated with increased lifespan, while accumulated DNA damage contributes to aging. Epigenetics: Chromatin modifications and non-coding RNAs also regulate aging, influencing gene expression patterns over the lifespan. Physiological Changes Reproductive Senescence: Nematodes exhibit a decline in reproductive capacity with age, which is linked to changes in germline and somatic cells. Neuromuscular Decline: Age-related deterioration in muscle and neuronal function is observed, leading to reduced motility and sensory perception. Metabolic Shifts: Aging nematodes undergo metabolic changes, including alterations in lipid metabolism and energy production.