title: Chemical imaging of lipid droplets in muscle tissues using hyperspectral coherent Raman microscopy.
abstract: The accumulation of lipids in non-adipose tissues is attracting increasing attention due to its correlation with obesity. In muscle tissue, ectopic deposition of specific lipids is further correlated with pathogenic development of insulin resistance and type 2 diabetes. Most intramyocellular lipids are organized into lipid droplets (LDs), which are metabolically active organelles. In order to better understand the putative role of LDs in pathogenesis, insight into both the location of LDs and nearby chemistry of muscle tissue is very useful. Here, we demonstrate the use of label-free coherent anti-Stokes Raman scattering (CARS) microscopy in combination with multivariate, chemometric analysis to visualize intracellular lipid accumulations in ex vivo muscle tissue. Consistent with our previous results, hyperspectral CARS microscopy showed an increase in LDs in tissues where LD proteins were overexpressed, and further chemometric analysis showed additional features morphologically (and chemically) similar to mitochondria that colocalized with LDs. CARS imaging is shown to be a very useful method for label-free stratification of ectopic fat deposition and cellular organelles in fresh tissue sections with virtually no sample preparation.
authors.affiliation: Molecular Spectroscopy Department, Max Plank Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Billecke
authors.forename: Gianluca
authors.initials: G
authors.lastname: Rago
authors.forename: Madeleen
authors.initials: M
authors.lastname: Bosma
authors.forename: Gert
authors.initials: G
authors.lastname: Eijkel
authors.forename: Anne
authors.initials: A
authors.lastname: Gemmink
authors.forename: Philippe
authors.initials: P
authors.lastname: Leproux
authors.forename: Guillaume
authors.initials: G
authors.lastname: Huss
authors.forename: Patrick
authors.initials: P
authors.lastname: Schrauwen
authors.forename: Matthijs K C
authors.initials: MK
authors.lastname: Hesselink
authors.forename: Mischa
authors.initials: M
authors.lastname: Bonn
authors.forename: Sapun H
authors.initials: SH
authors.lastname: Parekh
mesh_terms: D000818:Animals; D059305:Diet, High-Fat; D008055:Lipids / Q000032:analysis*; D008297:Male; D008853:Microscopy / Q000379:methods; D008928:Mitochondria; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D008055:Lipids