Platinum Compound Toxicity in Mice

Six-weeks-old female BALB/cByJ mice (n = 45), Specific-Pathogen-Free (SPF), were obtained from Charles River Laboratories (L’Arbresle, France). The animals were acclimatized for 1 week at the ICBAS-UP Rodent Animal House Facility (Porto, Portugal) and randomly placed in individual ventilated cages (5 animals per cage), containing enrichment material. The mice were housed in the conditions described elsewhere [29 (link)]. The animals were randomly divided into three groups (15 animals/group), to be treated via intraperitoneal injection in single doses (200 µL) of either (i) cDDP (3.5 mg/kg body weight, in phosphate-buffered saline solution (PBS)), (ii) Pd₂Spm (3.0 mg/kg body weight, in PBS and in 1% dimethylsulfoxide (DMSO)) or (iii) vehicle solution (PBS: H₂PO₄ 1.5 mM, Na₂HPO₄ 4.3 mM, KCl 2.7 mM, NaCl 150 mM, pH 7.4). All solutions injected were sterile filtered. The physical condition of the animals was monitored, and all animals were weighed at the start and end of experiments (20.1 ± 1.7 g and 20.3 ± 1.6 g, respectively). Five animals per group were sacrificed at 1, 12, and 48 h post-injection, with pentobarbital intraperitoneal injection (120 mg/kg) followed by cardiac puncture. One control mouse developed inflammation and was thus excluded from the cohort. Mice brains were excised, snap frozen in liquid nitrogen, and stored (−80 °C) until extraction.