Evaluating PIP and DOX in Osteosarcoma

Female Balb/c athymic mice (5–6 weeks old) were purchased from Vital River Laboratory Animal Technology (Beijing, China).This study was approved by the ethics committee of the First Affiliated Hospital of Shandong First Medical University (no. SYDWLS 2022014, 2022-05-10). All animal experimental practices were in accordance with the National Research Council's Guide for the Care and Use of Laboratory Animals. The right axilla (forearm) of each mouse was injected with 5 × 10⁷ 143B cells (log phase) suspended in 0.15 ml PBS. When tumors grew to approximately 100 mm³, rats were randomized into four groups (n = 5): control (saline), PIP (30 mg/kg), DOX (3 mg/kg), and PIP + DOX (30 mg/kg and 3 mg/kg, respectively). PIP was administered intraperitoneally once a day, while DOX was administered intraperitoneally every three days. The same volume of saline was injected intraperitoneally daily in the controlled group. Vernier callipers were used to conduct tumour size survey on third day basis. Tumour volumetric calculation was calculated as follows: $$\text{Tumour}\text{volume}=0.5\times L\times W^2$$ L and W were the long and short diameter of the tumour.The experiment was terminated when the tumour volume reached up to 2000 mm³. Tumour-bearing mice were weighed, and the primary tumour of each mouse was removed for further study.