In vivo anticancer efficacy study

In order to evaluate the therapeutic effect, 1 × 10⁷ H₂₂ cells were subcutaneously injected into the right front armpit of male Kunming mice (20 ± 2 g) to produce a tumor-bearing mice model. The successfully modeled mice with tumor volume not less than 100 mm³ were randomly divided into 9 groups, each group 10 mice. The first day of treatment was set as Day 0. The mice were injected with water for injection (model group), doxorubicin solution (5.0 mg/kg), DOX-LIP (5.0 mg/kg), DOX-PEC-NP (5.0, 2.5 and 1.0 mg/kg) and DOX-PEC-NC (5.0, 2.5 and 1.0 mg/kg) once a day via tail vein on Day 0, 4 and 8, respectively. The body weight and tumor volume of the mice were measured daily, and the general status was observed as well. Tumor volume was calculated using the formula (a × b²/2), where a and b denote the longest and shortest dimensions of the tumor tissues, respectively. All the mice were sacrificed on day 10, the tissues of tumor, thymus and spleen were collected and weighed, and thymus index or spleen index was calculated by equation of Thymus (Spleen) index = Weight of thymus (spleen) (mg)/ Weight of mouse (g). The inhibitory rate of tumor growth was calculated by the following equation using the mean weight of tumor tissues of model group as 100%, where W¯testgroup and W¯modelgroup was the mean weight of tumor tissues of test and model group, respectively.