Detection of doxorubicin hydrochloride accumulation in the rat brain after morphine treatment by mass spectrometry

Abstract

Keywords: blood-brain barrier, doxorubicin, morphine, rodent model, mass spectrometry 2 ABSTRACT Purpose: The blood brain barrier discriminates the access of several molecules into the brain. This hampers the use of some drugs, as doxorubicin, potentially active for treatment of brain tumors. We explored the feasibility of active modification of the blood brain barrier protection, by using morphine pretreatment, to allow doxorubicin accumulation into the brain in an animal model. Methods:Rats were pretreated with different doses of intraperitoneal morphine before injection of doxorubicin (12 mg/kg). Quantitative analysis of doxorubicin was performed by mass spectrometry.Acute hearth and kidney damage was analyzed by measuring doxorubicin accumulation, LDH activity and malondialdehyde plasma levels. Results: The concentration of doxorubicin was significantly higher in all brain areas of rats pretreated with morphine than in control tissues (P <0.001). This was evident only at therapeutic morphine dose (10 mg/kg, three times over 24 hours), while lower doses (2.5 and 5 mg/kg) were not associated with doxorubicin accumulation.Pretreatment with morphine did not induce an elevation of LDH activity or of lipid peroxidation compared to controls. Conclusion: Our data suggest that morphine pre-treatment is able to allow doxorubicin penetration inside the brain, by modulating the blood-brain barrier. This is not associated with acute cardiac or renal toxicity. These preliminary results will enable us to generate novel therapeutic approaches to refractory or recurrent brain tumors, and might be useful in other human diseases of the central nervous system in which molecules usually stopped by the blood brain barrier may have a therapeutic impact.3

Morphine facilitates doxorubicin penetration in the central nervous system: a new prospect for therapy of brain tumors

“…Coadministration of morphine did not increase the levels of DOX in heart and kidney tissues. Plasma LDH activity and MDA levels, as markers of acute cardiotoxicity, were similar in rats treated with DOX alone compared to those also receiving morphine [11].…”

“…However, this analysis does not reliably detect large molecules that use P-gp pomp efflux to circumvent BBB. In contrast, our study used mass spectrometry, a highly precise, reliable and sensitive method, to detect and quantify the penetration of agents as DOX into the brain [11].…”

“…Coadministration of morphine did not increase the levels of DOX in heart and kidney tissues. Plasma LDH activity and MDA levels, as markers of acute cardiotoxicity, were similar in rats treated with DOX alone compared to those also receiving morphine [11].Thus, it is conceivable that morphine inhibiting P-gp localized on BBB, neurons and glial cells could increase the access of DOX to the brain competing with the same efflux transporter that very efficiently removes these drugs from the CNS [2]. …”

The Use of Anthracyclines for Therapy of CNS Tumors

“…In order to find a safe and reliable way to deliver anticancer agents within the brain for the treatment of brain tumors, our group has recently investigated the possibility to permeabilize BBB by using morphine for delivery of DOX into the rat brain [79, 80]. …”

“…three times in 24 h) allows an accumulation of DOX (12 mg/kg, i.p. 1 h after the last injection of morphine) within the rat brain by LC-MS/MS mass spectrometry [79]. DOX concentration was significantly higher in all brain areas of animals pretreated with morphine in comparison to the group of animals treated with DOX alone: + 254% vs DOX alone in the cerebral hemispheres; + 308% vs DOX alone in the cerebellum; + 256% vs DOX alone in the brainstem.…”