ID #746 Pharmacological modulation of blood-brain barrier increases permeability of doxorubicin into the rat and zebrafish brain
Bianca Tirinnanzi, Rachele Amato, Elena Pasquinelli, Chiara Ester La Torre, Laura Giunti, Laura Calonaci, Barbara Castelli, Milena Guidi, Marco Tellini, Marco Di Nicola, Carla Fonte, Iacopo SardiAbstract
Background
Limited penetration of chemotherapeutic agents across the blood–brain barrier (BBB) remains a major obstacle in neuro-oncology. In rodent models, opioid pre-treatment has been shown to transiently increase BBB permeability and enhance doxorubicin (DOX) brain accumulation. However, reliance on mammalian models alone limits experimental scalability and early-stage screening of BBB modulation strategies. There is an increasing need for complementary vertebrate models that faithfully reproduce BBB properties while enabling efficient preclinical investigation.
Methods
We performed a comparative preclinical study assessing brain penetration of DOX and morphine in two experimental models developed within the same research framework: rat and adult zebrafish. Animals received intraperitoneal injections of vehicle, DOX (12 ng/mg fish), and morphine (5 ng/mg fish). Brain tissues were collected 1-hour post-injection and analyzed by targeted HPLC–MS/MS. Detected compound concentrations were normalized to brain mass. Zebrafish experiments were designed to parallel previously established murine protocols, enabling direct qualitative comparison across species.
Results
Consistent with our previously published murine data, DOX was detectable in rat brain tissue following administration, while morphine exhibited enhanced intrinsic brain penetration (p < 0.001). In zebrafish, neither compound was detected in vehicle-treated controls, whereas DOX was measurable in brain tissue after administration (mean ∼0.055 ng/mg brain). Morphine showed substantially higher brain accumulation in zebrafish (mean ∼2.63 ng/mg brain), reflecting trends observed in the rat model. These findings confirm cross-species concordance in BBB permeability patterns and validate analytical feasibility in zebrafish.
Conclusions
This cross-species analysis demonstrates that zebrafish recapitulates key features of BBB drug penetration observed in mammalian models. These findings support the use of zebrafish as an innovative and complementary platform for BBB-focused pharmacokinetic studies. Ongoing experiments will evaluate the impact of morphine pre-treatment on DOX brain delivery across both models, with potential implications for the development of improved therapeutic strategies in pediatric neuro-oncology.