Liver Injury Assessment by Vetscan VS2 Analyzer and Most Frequently Used ALT/GTP Reagent.
OBJECTIVE
Liver injury is estimated by serum alanine aminotransferases (ALT) levels in experimental animal models. Laboratories use various techniques to measure ALT levels including assay reagents and chemistry analyzers. VetScan VS2 (VS2) is widely used in veterinary clinics and research laboratories for highly reproducible, convenient and effective testing. Alternatively, ALT liquid reagent is used by laboratories to estimate liver injury in animal studies. The aim of this study was to perform comparative analyses of data obtained from these two assays in two different animal models.


METHODS
In this study, we used two different mouse models and compared the ALT levels measured using VetScan VS2 chemistry analyzer and ALT liquid reagent. Immunohistochemical analysis of hepatic tissue was also performed to document liver pathology. The first model is a high fat diet feeding model that results in a mild hepatic steatosis (fat accumulation in the liver) without elevation of ALT levels. For a severe liver injury model, we employed a hepatotoxin-induced liver injury model (carbon tetrachloride, CCl4), which leads to the development of hepatic fibrosis and very high ALT levels.


RESULTS
VetScan VS2 and ALT reagent gave different values of ALT for all animal groups. However, linear regression analysis showed a significantly high association between ALT levels obtained by VS2 and ALT liquid reagent in a high-fat feeding model with no liver injury. For the CCl4induced liver injury model, serum dilution (5 and 10 times) was performed to obtain accurate results with ALT reagent. ALT levels acquired from both techniques showed a close association. Interestingly, this correlation was closer when serum was diluted 5 fold.


CONCLUSIONS
This study demonstrates that both methods give similar results when evaluating liver injury in animal studies. However, the serum dilution factor is critical for severe liver injury assessment when using ALT reagent and requires some optimization. In this regard, VetScan VS2 is easier to use and gives comparable results.
Department of Medicine, University of Louisville School of Medicine, USA; Robley Rex Veteran's Medical Center, USA.
Vatsalya
V
Vatsalya
Department of Pharmacology and Toxicology, University of Louisville School of Medicine, USA.
Diana
D
Avila
Department of Surgery, University of Louisville School of Medicine, USA.
Jane C
JC
Frimodig
Department of Medicine, University of Louisville School of Medicine, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, USA.
Shirish S
SS
Barve
Department of Medicine, University of Louisville School of Medicine, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, USA; Robley Rex Veteran's Medical Center, USA.
Craig J
CJ
McClain
Department of Medicine, University of Louisville School of Medicine, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, USA.
Leila
L
Gobejishvili
ALT; Biochemical markers; CCl4; Liver injury; Stable liquid reagent; VetScan VS2