title: Fluorescence spectroscopy to diagnose hepatic steatosis in a rat model of fatty liver.
abstract: BACKGROUND
  Steatosis is diagnosed on the basis of the macroscopic aspect of the liver evaluated by the surgeon at the time of organ extraction or by means of a frozen biopsy.
  
  
  OBJECTIVE
  In the present study, the applicability of laser-induced fluorescence (LIF) spectroscopy was investigated as a method for the diagnosis of different degrees of steatosis experimentally induced in rats.
  
  
  METHODS
  Rats received a high-lipid diet for different periods of time. The animals were divided into groups according to the degree of induced steatosis diagnosis by histology. The concentration of fat in the liver was correlated with LIF by means of the steatosis fluorescence factor (SFF).
  
  
  RESULTS
  The histology classification, according to liver fat concentration was, Severe Steatosis, Moderate Steatosis, Mild Steatosis and Control (no liver steatosis). Fluorescence intensity could be directly correlated with fat content. It was possible to estimate an average of fluorescence intensity variable by means of different confidence intervals (P=95%) for each steatosis group. SFF was significantly higher in the Severe Steatosis group (P<0.001) compared with the Moderate Steatosis, Mild Steatosis and Control groups.
  
  
  CONCLUSIONS
  The various degrees of steatosis could be directly correlated with SFF. LIF spectroscopy proved to be a method capable of identifying the degree of hepatic steatosis in this animal model, and has the potential of clinical application for non-invasive evaluation of the degree of steatosis.
authors.affiliation: Faculty of Medicine of Ribeirão Preto, Institute of Physics of São Carlos (IFSC), University of São Paulo (USP), São Carlos, SP, Brazil.
authors.forename: Gustavo Ribeiro
authors.initials: GR
authors.lastname: de Oliveira
authors.forename: Ajith K
authors.initials: AK
authors.lastname: Sankarankutty
authors.forename: Orlando
authors.initials: O
authors.lastname: Castro e Silva
authors.forename: Juliana
authors.initials: J
authors.lastname: Ferreira
authors.forename: Cristina
authors.initials: C
authors.lastname: Kurachi
authors.forename: Sergio
authors.initials: S
authors.lastname: Zucoloto
authors.forename: Hélio
authors.initials: H
authors.lastname: Vannucchi
authors.forename: Alceu Afonso
authors.initials: AA
authors.lastname: Jordão
authors.forename: Júlio Sergio
authors.initials: JS
authors.lastname: Marchini
authors.forename: Vanderlei Salvador
authors.initials: VS
authors.lastname: Bagnato
mesh_terms: D000818:Animals; D005234:Fatty Liver / Q000175:diagnosis*; D007834:Lasers; D051381:Rats; D013050:Spectrometry, Fluorescence / Q000379:methods*