Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.30.362160v1?rss=1 Authors: Azeem, M., Qiaser, R., Ranade, A., Karim, A., Elmoselhi, A. Abstract: Hind-limb unloaded (HU) mouse is a well-recognized model of muscle atrophy; however the molecular changes in the skeletal muscle during unloading are poorly characterized. We have used Fourier transform infrared (FTIR) and Raman spectroscopy to evaluate the structure and behavior of signature molecules involved in regulating muscle structural and functional health. The FTIR and the Raman spectroscopic analysis of gastrocnemius muscles was compared between 16-18 weeks old HU c57Bl/6J mice and ground-based controls. The molecular components of the samples were identified by using the FTIR spectra from the control and the unloaded samples. The Raman spectra showed that the signals for asparagine and glutamine were reduced in HU mice, possibly indicating increased catabolism. The peaks for hydroxyproline and proline were split, pointing towards molecular breakdown and reduced tendon repair. We also report a consistently increased intensity in > 1300 cm-1 range in the Raman spectra along with a shift towards higher frequencies in the HU mice, indicating activation of sarcoplasmic reticulum (SR) stress during HU. Copy rights belong to original authors. Visit the link for more info