2.5. Hepg2 cell xenograft model and fluorescent imaging in vivo

The human hepatocarcinoma cell line Hepg2 was obtained from ATCC (Manassas, VA) and maintained in H‐DMEM (Thermo Fisher) containing 100 U/mL penicillin, 100 μg/mL streptomycin and 10% FBS. Cells were incubated in a 5% CO₂‐humidified incubator at 37°C. Hepg2 cells (5 × 10⁶) were injected subcutaneously into the dorsal region of BALB/c nude mice. 1.5 × 10⁶ GFP‐labelled hAMSCs in 300 μL 1 × PBS or 300 μL 1 × PBS alone as a control was intravenously injected after 6, 12 and 18 days of Hepg2 transplantation. The longest size (a) and the shortest size of (b) tumour were measured with vernier calliper (Mitutoyo Co., Tokyo, Japan) every day for 24 days. The tumour volume calculation formula is V= (1/2)ab². Eighteen days after cell injection, the mice were anaesthetized first, and the mice were visualized with whole‐body fluorescent imaging system (LB983; Berthold, Germany). Then, the mice were killed, and the tissues of tumour, heart, liver, brain, kidney, spleen, lung and pancreas were isolated and visualized with whole‐body fluorescent imaging system.