A combined prophylactic modality of podophyllotoxin and rutin alleviates radiation induced injuries to the lymphohematopoietic system of mice by modulating cytokines, cell cycle progression and apoptosis.

The present study was conceptualized to delineate radioprotective efficacy of a formulation G-003M (a combination of podophyllotoxin and rutin) against radiation-induced damage to the lymphohematopoietic system of mice. C57BL/6J mice, treated with G-003M 1 h prior to 9 Gy lethal dose, were assessed for reactive oxygen species (ROS)/nitric oxide (NO) generation, antioxidant alterations, Annexin V/PI and TUNEL staining for apoptosis, modulation of apoptotic proteins, cell proliferation, histological alterations in thymus and cell cycle arrest in bone marrow cells. Induction of granulocyte colony-stimulating factor (G-CSF), granulocytes macrophage colony-stimulating factor (GM-CSF), interleukin-IL-6, IL-10, IL-1 alpha, and IL-1 beta in response to G-003M was also evaluated in different groups of mice. Haematopoietic reconstitution with G-003M was explored by examining endogenous spleen colony-forming units (CFU-S) in irradiated animals. G-003M significantly inhibited ROS/NO, malondialdehyde (MDA) and restored cellular antioxidant glutathione in the thymus of irradiated animals. G-003M pre-treatment significantly (p < 0.001) restrained apoptosis in thymocytes via upregulation of Bcl2 and down-regulation of Bax, p53 and caspase-3. Stimulation of cell proliferation and inhibition of apoptosis by G-003M, restored architecture of thymus in irradiated animals within 30 days as evaluated by histological analysis. G-003M arrested cells at the G2/M phase by inducing reversible cell cycle arrest. Peak expression of G-CSF (45-fold) and IL-6 (60-fold) as well as moderate induction of GM-CSF, IL-10, IL-1 alpha by G-003M helped in haematopoietic recovery of irradiated mice. A higher number of endogenous CFU-S in G-003M pre-treated irradiated mice suggested haematopoietic recovery. Data obtained from the current study affirms that G-003M can be proved as a potential radioprotective agent against radiation damage.