Fig 1.
HT29-GFP colon cancer experimental liver metastasis.
(A) HT-29-GFP cells (5×105 in 50 μl with 50% Matrigel) were injected into the superior pole and inferior pole of the spleen (arrows), respectively. (B) Three weeks after injection, liver metastasis was confirmed by laparotomy, which was resected and cut into 3-mm3 blocks. Each tumor fragment was implanted by surgical orthotopic implantation (SOI) in the left lobe of the liver on other nude mice. (C) Representative images of liver metastasis established after spleen injection. The large tumor in the liver strongly expressed GFP. (GFP, green fluorescent protein; BF, bright field)
Fig 2.
Schematic diagram of the experimental design.
(A) Fourteen mice were randomized into 2 groups; FGS: n = 7, BLS: n = 7. (B) Timeline from orthotopic implantation. Four weeks after implantation, all mice were treated with FGS or BLS. Twenty-eight days after the surgery, all mice underwent laparotomy to detect GFP for evaluation of recurrence. After the laparotomy, follow-up examination for survival was continued. (FGS, fluorescence-guided surgery; BLS, bright-light surgery).
Fig 3.
Pre-operative and post-operative images from the orthotopic liver metastasis model treated with BLS.
(A)—(C) Upper panels show bright field images, and lower panels are images of tumor fluorescence obtained with the OV100. At low magnification, residual tumor fluorescence was marginally detected. (B) However, at high magnification, residual tumor fluorescence was clearly visualized (arrows) (C). Arrowheads show residual tumor fluorescence in B and C. (D) Resected specimen. Magnifications are indicated above the columns.
Fig 4.
Pre-operative and post-operative images from the orthotopic liver metastasis model treated with FGS.
(A)—(C) Upper panels show bright field images, and lower panels are images of tumor fluorescence obtained with the OV100. Residual tumor fluorescence could not be detected even at high magnification (C). (D,F,H) Pre-FGS tumor fluorescence was clearly visualized with the Dino-Lite imaging system. (E,G,I) Dino-Lite imaging showed no evidence of tumor after FGS. (J-K) Dino-Lite settings. (J) After exposing the left lobe of the liver, the mouse was put under the Dino-Lite. (K) Connection between the Dino-Lite and computer. Tumor fluorescence was imaged on the monitor during FGS. Magnifications are indicated above the columns.
Fig 5.
Histological tumor margin of resected specimen.
(A)-(C) H&E staining of resected specimen. (A) In the mouse treated with FGS, viable cancer tissue (marked by an asterisk) is surrounded by normal liver tissues. (B) High magnification of (A). (C) In the BLS-treated mouse, viable cancer cells are visible along the resection line. Arrows show residual cancer tissue. Dashed lines separate viable cancer and normal liver tissue. Scale bars: 200 μm.
Fig 6.
Bar graph of residual tumor area after surgery.
No residual tumor was detected in the FGS group. Residual tumor area after BLS was relatively large. Error bar shows SD. **P<0.01.
Fig 7.
Evaluation of tumor fluorescence at day 28 after surgery.
(A) Upper panel shows the bright field image, and lower panel shows the GFP tumor fluorescence image obtained with the OV100 at a magnification of 0.56. Laparotomy was performed at the 28th postoperative day. Bright field image shows tumor in the resection site in the liver (arrows). Strong GFP fluorescence from the tumor is seen in the lower panel. Arrows show recurrent tumor in the resection site. Arrowheads show operative scar on the liver. (B) The GFP tumor fluorescence area was significantly larger in the BLS group compared to the FGS group, where only autofluorescence was detected. Error bars show SD. *P<0.05.