3.6. In-Vivo Xenograft Tumor Models for Drug Testing

The experiments were conducted with Mus musculus var. albino mice weighing around 35–37 g which were supplied by The Institute of Drug Quality Control (Ho Chi Minh City, Vietnam). Immunodeficient mouse models were created and cared for by the Laboratory of Physiology and Animal Biotechnology and Laboratory of Tissue Engineering and Biomedical Materials (University of Science, VNU, Hochiminh City, Vietnam). The animal experiment protocol was approved by the Animal Care and Use Committee of the University of Science, VNU, Vietnam. MCF-7 cells (107) in 100 µL NaCl were injected subcutaneously on one back side of each mouse and the tumor size of each mouse was measured 5 days after cell transplantation. Then, at a stably tumor size-measured stage, mice were randomly divided into five groups with five mice per group: control, CDDP, Hep-F127, Hep-F127/CDDP, Hep-F127/CDDP/Cur treated mice. NaCl (100 µL) was injected intravenously into the control mice while 3 mg of CDDP/kg, 12 mg Hep-F127, 15 mg of Hep-F127/CDDP (with around 3 mg of CDDP in the nanocomplex) and 18 mg of Hep-F127/CDDP/Cur (with around 3 mg of CDDP and 3 mg nanocurcumin in the nanocarrier) were administed to four treated mice, respectively, per 5 days. The tumor size of the control and drug-treated mice were measured by calipers at the time of administrating the drug aside from every 2 days. Moreover, the tumor volume of both the drug untreated and treated groups was calculated based on the formula of Tomayko, in which the minor axis and the major axis of tumor were the required measurements. Additionally, weight was estimated at the similar time as the tumor measurements [29]. All mice were housed in clean cages and maintained according to the institutional guidelines on animal welfare. Mice with tumors were euthanized after 15 days, and the xenografted and materials-treated tumors were evaluated by superoxide dismutase 2 (SOD2) assay, immunohistochemical staining and hematoxylin & eosin (H&E) staining. Hematoxylin-stained cellular nucleic acids show a deep blue-purple color via a completely non-understood complexation. Nuclei are stained blue in eosin and the extracellular matrix is stained pink [30].