Measuring chemical changes during aging in vivo with stimulated Raman scattering microscopy

Aging related biological mechanisms are often difficult to probe in situ without exogenous fluorophores. Here, we leverage label-free stimulated Raman scattering (SRS) microscopy to provide new insights into aging in C. elegans. We demonstrate multispectral SRS imaging of whole worms in vivo with quantitative chemical insights across different ages. We show that both lipid and protein synthesis and compartmentalization are associated with aging in worms. We additionally use SRS in combination with simultaneous two-photon fluorescence imaging to characterize the putatively aberrant protein accumulation. Moreover, we observe notable SRS image differences when worms are subjected to calorie restriction, suggesting a promising avenue towards understanding calorie-restriction's enhancing effects on longevity when coupled to proteomic and metabolomic analysis.