Signature molecular changes in the skeletal muscle of hindlimb unloaded mice

Muhammad Azeem; Rizwan Qaisar; Asima Karim; Anu Ranade; Adel Elmoselhi

doi:10.1016/j.bbrep.2021.100930

Signature molecular changes in the skeletal muscle of hindlimb unloaded mice

Biochem Biophys Rep. 2021 Jan 29:25:100930. doi: 10.1016/j.bbrep.2021.100930. eCollection 2021 Mar.

Authors

Muhammad Azeem¹, Rizwan Qaisar², Asima Karim², Anu Ranade², Adel Elmoselhi²

Affiliations

¹ Department of Applied Physics and Astronomy, College of Sciences, University of Sharjah, 27272, Sharjah, United Arab Emirates.
² Department of Basic Medical Sciences, College of Medicine, University of Sharjah, 27272, Sharjah, United Arab Emirates.

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 Raman spectroscopy to evaluate the structure and behavior of signature molecules involved in regulating muscle structural and functional health. The Raman spectroscopic analysis of gastrocnemius muscles was compared between 16-18 weeks old HU c57Bl/6J mice and ground-based controls. The 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.

Keywords: Molecular changes; Raman spectroscopy; SR stress; Skeletal muscle.