Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan

This study reports on the use of Fourier transform infrared (FTIR) microspectroscopy imaging to investigate biochemical changes occurring during C. elegans lifespan. C. elegans wild-type (N2) and the tub-1 mutant strain were cultured in agar plates. FTIR imaging was performed on single worms in transmission mode at day 8, 11, and 15. Principal component analysis was then performed to analyze the spectra acquired during C. elegans lifespan. The FTIR spectra were clustered in three groups corresponding to the spectra acquired from the worms at day 8, 11, and 15. The results showed major changes in lipids (vibration 1744 cm−1 assigned to C O stretching) and proteins (vibrations 1648 cm−1 assigned to C O stretching of amide I and 1548 cm−1 assigned to N H bending and C–N stretching in amid II). The vibration assigned to glycogen around 1155 cm−1 was present in the spectra acquired at day 8 and 11 but the peak area decreased by 49.3% and 73.3% in the spectra acquired at day 15 respectively from WT(N2) and tub-1 mutant strain. Furthermore, PC-1 loadings as a function of wavenumbers show that the presence of the vibration 1698 cm−1, attributed to antiparallel β-sheet, could indicate the formation of lipofuscin. The results obtained demonstrate that FTIR imaging could be used as a tool to monitor biochemical changes during lifespan studies, which could bring additional information to our understanding of longevity.