In vivo evaluation of the neuroprotective effects of melittin on doxorubicin-induced acute and chronic neurotoxicity in mice

Doxorubicin (DOX) is a widely used chemotherapeutic agent whose clinical application is limited by severe neurotoxic side effects, manifesting as cognitive dysfunction and neuronal injury following both acute and chronic exposure. Neuroinflammation, oxidative stress, and Apoptosis are central mechanisms underlying DOX-induced neurotoxicity. Melittin, a bioactive neuropeptide derived from bee venom, has demonstrated potent anti-inflammatory and cytoprotective properties; however, its effects on DOX-induced neurotoxicity remain insufficiently characterized. Mice were assigned to acute (DOX-4) and chronic (DOX-3) exposure protocols. Melittin was administered at doses of 0.1, 0.2, and 0.4 mg/kg. Neuroprotective efficacy was evaluated through biochemical markers of oxidative stress, including malondialdehyde (MDA) and reduced glutathione (GSH). Additionally, neuroinflammation (NF-κB, iNOS, nNOS, TNF-α, IL-6) and Apoptosis (Caspase-3) were assessed via immunohistochemical and molecular analyses in brain tissue. In the present study, we investigated the neuroprotective effects of melittin in murine models of acute and chronic DOX-induced neurotoxicity. Male Balb/c mice were exposed to acute (4 mg/kg, 2 weeks) or chronic (3 mg/kg, 6 weeks) DOX administration, with melittin (0.1, 0.2, or 0.4 mg/kg) administered intraperitoneally prior to DOX administration. Molecular alterations were evaluated in brain tissue by quantitative Real-Time PCR analysis of NF-κB, TNF-α, IL-6, inducible and neuronal nitric oxide synthases (iNOS, nNOS), and Caspase-3. Neuroprotective efficacy was evaluated through biochemical markers of oxidative stress, including malondialdehyde (MDA) and reduced glutathione (GSH). Finally, NF-κB protein expression was further assessed by immunohistochemistry. DOX administration significantly upregulated pro-inflammatory cytokines, NF-κB signaling, MDA level, iNOS and Caspase-3 expression, while suppressing nNOS expression and GSH level in both acute and chronic neurotoxicity models. Melittin treatment markedly attenuated DOX-induced neuroinflammatory and apoptotic responses in a dose-dependent manner, with the highest dose restoring molecular parameters toward control levels. These protective effects were more pronounced in the chronic neurotoxicity model. Our findings demonstrate that melittin exerts a robust neuroprotective effect by modulating the oxidative-inflammatory-apoptotic axis and restoring redox homeostasis in the brain. Melittin may represent a promising neuropeptide-based therapeutic strategy for mitigating chemotherapy-associated neurotoxicity.

Apoptosis; Doxorubicin; Melittin; Neuroinflammation; Neurotoxicity; Oxidative stress.