Anti-radiation effect and mechanism studies of ethanol extracts from Spatholobus suberectus and its active component catechin

To study the anti-radiation effect and mechanism of ethanol extracts from Spatholobus suberectus and its active component catechin, ICR mice were exposed to 6Gy irradiation and randomly divided into normal group, model group, positive control group (amifostine, 43.6 mg•kg⁻¹, iv 30 min before irradiation), SSD group (10, 20, 40 g•kg⁻¹) and catechin group (50, 100, 200 mg•kg⁻¹). The mice were administered the appropriate drugs once a day after irradiation for 28 consecutive days. Blood samples were collected from the tail end and the number of peripheral blood cells was counted before irradiation and on day 1, 3, 7, 14, 21 and 28 using a microcell counter. Changes of thymus and spleen index of mice on day 7 were observed. The serum SOD, GSH-Px activity and MDA level were detected by the colorimetric method. The colony forming ability of bone marrow hematopoietic progenitor cells on day 7 was detected by semi solid culture method. The HE staining was adopted to observe the pathological changes. The apoptosis of bone marrow cells was detected by flow cytometry. The expression of cleaved caspase-3 and Bax of bone marrow cells were measured separately by western-blotting and immunohistochemistry method. SSD and catechin can both significantly revert the irradiated-induced decline in hematological parameters (RBC, WBC, PLT, Hb), improve thymus and spleen index, significantly enhance serum SOD and GSH-Px activity and decrease the MDA level. The proliferation and differentiation of hematopoietic progenitor cells in bone marrow were promoted, the apoptosis of bone marrow cells was significantly up-regulated and the expression of cleaved caspase-3 and Bax was significantly reduced in SSD and catechin group. SSD and catechin have significant anti-radiation effect and its mechanism may be related to hematopoietic promoting, antioxidant and anti-apoptotic effects.