Palliative effects of lutein intervention in gamma-radiation-induced cellular damages in Swiss albino mice

Study of the Radiosensitizing and Radioprotective Efficacy of Bromelain (a Pineapple Extract): In Vitro and In Vivo

This study hypothesizes that, bromelain (BL) acts as radiosensitizer of tumor cells and that it protects normal cells from radiation effects. In vitro and in vivo studies have been carried out to prove that assumption. In vitro MTT cell proliferation assay has shown that the irradiated Ehrlich ascites carcinoma (EAC) cell line could be sensitized by BL pretreatment. In vivo: animals were randomly divided into 5 groups, Group 1: control (PBS i.p for 10 days), Group 2: Ehrlich solid tumor (EST) bearing mice, Group 3: EST + γ-radiation (fractionated dose, 1 Gy × 5), Group 4: EST + BL (6 mg/kg, i.p), daily for 10 days, Group 5: EST + BL for 10 days followed by γ-irradiation (1 Gy × 5). The size and weight of tumors in gamma-irradiated EST bearing mice treated with BL decreased significantly with a significant amelioration in the histopathological examination. Besides, BL mitigated the effect of γ-irradiation on the liver relative gene expression of poly ADP ribose polymerase-1 (PARP1), nuclear factor kappa activated B cells (NF-κB), and peroxisome proliferator-activated receptor α (PPAR-α), and it restored liver function via amelioration of paraoxonase1 (PON1) activity, reactive oxygen species (ROS) content, lipid peroxidation (LPO) and serum aspartate transaminase (AST), alanine transaminase (ALT), and albumin (ALB). It is concluded that BL can be considered as a radio-sensitizer and radio-protector, suggesting a possible role in reducing radiation exposure dose during radiotherapy.

Radioprotection and Radiomitigation: From the Bench to Clinical Practice

The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed.