LAUSR

The purpose of this study was to detect cell death in the liver of mice treated with thioacetamide (TAA) using fluorescence bioimaging and compare this outcome with that using conventional histopathological examination. At 6 weeks of age, 24 mice were randomly divided into three groups: group 1 (G1), control group; group 2 (G2), fluorescence probe control group; group 3 (G3), TAA-treated group. G3 mice were treated with TAA. Twenty-two hours after TAA treatment, G2 and G3 mice were treated with Annexin-Vivo 750. Fluorescence in vivo bioimaging was performed by fluorescence molecular tomography at two hours after Annexin-Vivo 750 treatment, and fluorescence ex vivo bioimaging of the liver was performed. Liver damage was validated by histopathological examination. In vivo bioimaging showed that the fluorescence intensity was increased in the right upper part of G3 mice compared with that in G2 mice, whereas G1 mice showed no signal. Additionally ex vivo bioimaging showed that the fluorescence intensity was significantly increased in the livers of G3 mice compared with those in G1 or G2 mice (p < 0.05). Histopathological examination of the liver showed no cell death in G1 and G2 mice. However, in G3 mice, there was destruction of hepatocytes and increased cell death. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed many cell death features in the liver of G3 mice, whereas no pathological findings were observed in the liver of G1 and G2 mice. Taken together, fluorescence bioimaging in this study showed the detection of cell death and made it possible to quantify the level of cell death in male mice. The outcome was correlated with conventional biomedical examination. As it was difficult to differentiate histological location by fluorescent bioimaging, it is necessary to develop specific fluorescent dyes for monitoring hepatic disease progression and to exploit new bioimaging techniques without dye-labeling.