Melanin Nanoparticles (MNPs) provide protection against whole-body ɣ-irradiation in mice via restoration of hematopoietic tissues

Abstract

During radiotherapy, ionizing irradiation interacts with biological systems to produce free radicals, which attack various cellular components. The hematopoietic system is easily recognized to be radiosensitive and its damage may be severe. Melanin nanoparticles (MNPs) act as free radical scavengers prepared by polymerization of dopamine. In this study, a total of 110 male BALB/C mice were divided into five equal groups. Each group contained 22 mice. Mice of group A did not receive MNPs or irradiation (control group), group B was injected intraperitoneally (i.p.) with 50 mg/kg MNPs. Mice of group C and D were exposed to a dose of 7 Gy ɣ-irradiation and injected with the same dose of MNPs as in group B either 30 min pre- or post-irradiation, and group E was exposed to a dose of 7 Gy ɣ-irradiation only. The impact of MNPs on peripheral blood, spleen, and DNA damage induced by irradiation was evaluated by blood count, histopathology of the spleen, and comet assay for the DNA in the bone marrow at 1, 4, 8, and 12 days post-irradiation. Results of group E compared with control group (A) showed a significant depression in complete blood count. Additionally, histopathological observation showed the absence of megakaryocytes with delayed time post-irradiation, deposition of eosinophilic protein of their spleen appeared, as well as a remarkable decrease in spleen size was observed. Moreover, ɣ-irradiation-induced DNA damage as can be inferred from a significant increase by about 5-10 folds in all comet parameters (% of DNA, tail length, tail moment, and olive moment) in the DNA of the bone marrow. In contrast, pre-post treatment with MNPs protected hematopoietic tissues against radiation damage, and therefore, enhanced the survival of mice with 40 % in groups (C&D) compared with 10 % to group (E) till 30 days post-irradiation. In conclusion, these results demonstrated that synthetic MNPs provide significant radioprotection to the hematopoietic tissues.

Emerging Nanotechnology and Advanced Materials for Cancer Radiation Therapy

“…Thus, our group further developed nano-droplets of PFC stabilized by albumin as an oxygen shuttle for tumor-specific delivery of oxygen with the help of tumor-focused low-intensity ultrasound (Figure 13). 2017, 29,1700996 Hemoglobin-based oxygen carrier [230,237] Perfluorocarbon (PFC) emulsions; BSA coated PFC emulsion; PFC loaded hollow Bi 2 Se 3 ; TaOx decorated with PFC nanodroplets [238][239][240][241] Mild hyperthermia [39,71,73] Increase tumor oxygenation by catalysis of endogenic H 2 O 2 MnO 2 nanopartilces; MnO 2 nanosheets@ upconversion; Au@MnO 2 core-shell [242][243][244][245][246][247] Polymer micelles encapsulating catalase and TaOx@catalase [248][249][250] Hypoxia-specific therapy accompany hypoxia-specific cytotoxicity of tirapazamine [58,251] X-ray controlled NO releasing [56] Radioprotection to reduce side effects Free radical scavengers CeO 2 nanoparticles [252,253] Melanin nanoparticles [254,255] MoS 2 dots [256] Oxygen-loaded nanoparticles were able to enhance tumor oxygenation triggered by the NIR laser. injected into tumorbearing mice under hyperoxic breathing.…”

Melanin is effective in protecting fast and slow growing fungi from various types of ionizing radiation

“…The radioprotective properties of melanins are of high interest for a number of different potential applications, including the development of novel and effective radioprotective materials for saving cancer patients undergoing radiation therapy from the side‐effects of ionizing radiation treatment, and protection of astronauts from space radiation in manned space missions. Data confirm that radioprotective properties of fungal melanins can be exploited in mammalian systems; in fact, it was recently reported that internal administration of melanin protected mice against experimental lethal irradiation (Schweitzer et al ., ; Kunwar et al ., ; Revskaya et al ., ; Rageh et al ., ).…”

Multimodal‐Imaging‐Guided Cancer Phototherapy by Versatile Biomimetic Theranostics with UV and γ‐Irradiation Protection

“…[18] We therefore explored the γ-irradiation protection function of MMNs on healthy female BALB/c mice. Mice were challenged with a lethal dose of γ-irradiation using 60 Co source.…”

“…Other than physical shielding and quenching of cytotoxic-free radicals, [20] melanin also showed abilities in modulation of pro-survival pathways, prevention of oxidative stress and potent immunomodulation. [18, 21] Therefore, MMNs might be useful and serve as a potential radioprotector to shield the normal organs of cancer patients who are undergoing high dose radiotherapy.…”