Nude Mouse Xenograft Model

BALB/c nude mice were bred at the animal facility of Chong Qing Medical University. The mice were housed in barrier facilities with a 12-hour light-dark cycle, with food and water available ad libitum. Transplantable tumors (induced by K562 cells subcutaneous inoculation of a mixture of 2 × 10⁷ actively growing K562 cells in 100 µL PBS and 100 µL of matrigel to the dorsal side of each nude mouse) were chopped into fragments (about 1.5 mm³), each of which was transplanted into the right or left axillary fossa of 25 nude mice. Palpable tumors of volume 100 to 200 mm³ were developed after 12 days and the mice were randomly divided into 5 groups (with 5 mice per group): negative control group; emodin 25, 50, 100 mg/kg groups and HU120mg/kggroup. The negative control group received 0.9% normal saline containing 1% DMSO. All of these drugs were injected intraperitoneally every day up to 12 days. Tumor size was measured once every 2 days in 2 perpendiculars, and tumor volume (TV) was calculated using the formula: (ab²)/2, where a and b refer to the longer and shorter dimensions, respectively. The body weight of the animals was measured 3 times a week at the same time as the tumor dimension measurement and the mortality was monitored daily. The tumor growth inhibition rate was calculated using the following formula: inhibition rate (%) = (mean tumor weight of negative control group − mean tumor weight of treatment group)/mean tumor weight of negative control group. This experiment was conducted in accordance with the guideline issued by the State Food and Drug Administration (SFDA of China). The animals were housed and cared in accordance with the guidelines established by the National Science Council of Republic China.