The effect of axenic dietary restriction on the age-related changes in C. elegans.

Axenic dietary restriction (ADR) is highly effective in extending lifespan of C. elegans but its effects on healthspan improvement is less well characterized. Using transmission electron microscopy, morphometric analyses, and functional assays, we found ADR can preserve tissue ultrastructure, including the cuticle, epidermis, and intestinal lumen, and reduce age-associated pathologies like gonad degeneration, uterine tumor clusters, pharyngeal deterioration, and intestinal atrophy. However, there was no notable improvement in behavioral and functional metrics. Our results underscore that lifespan extension through ADR does not inherently translate to broad healthspan improvements.