Antitumor effect of MTX-DG liposomes versus intact MTX in vivo

Two experiments with female mice of different ages (6 and 12 months) were carried out. At day 0, A/Sn female mice (n=18) were inoculated with ASF-LL cells as described earlier. The mice were treated with 4 IV injections of MTX (10 mg/kg; n=6) or equivalent dose of L-MTX-DG (n=6) in 0.2 mL of PBS with 1 mM EDTA, pH 7.0, on days 3, 5, 10, and 12. Control mice (n=6) received 0.2 mL of PBS with 1 mM EDTA via the same route.

The mice were monitored each third day for palpable tumor appearance (1–4 mm of size). For larger tumor nodules, individual mean tumor diameter (TD, mm) as an average of 3 perpendicular TDs was used as a measure of tumor size.23 The mice were monitored daily for health control and survival: animals at the end point of leukemic lymphoma (weight loss >20% and/or food rejection independently of tumor size) were immediately euthanatized.21

The significance of differences in averages was determined by using the Student’s t-test, and the results were presented as mean ± standard deviation.