Study On Anti-radiation And Anti-Leukemia Effect Of Fucoidan And Its Mechanisms

Laminaria japonica Aresch is a food which is full of nutrition. It is widely recognized that the extract of Laminaria japonica Aresch, Laminaria Japonica polysaccharides, plays multiple roles in pharmacological and biological functions in recent studys. This paper was performed on fucoidan , one of Laminaria Japonica polysaccharides, antiradiation and antitumor mechanism by apoptosis, and investigating the reasons by study the expression of some relative-apoptosis genes. The main results are as follows:The 60 Wistar rats were randomly divided into 6 groups (n=6): normal control group model group and 4 group with different dosage of fucoidan (100 mg/ kg 200 mg/ kg 300 mg/ kg, 400 mg/ kg). All the 60 rats were administered by gavage for 10 d , then whole-body irradiation with 9.0Gy 60Co Y -ray.The indexes of T,B lymphocyte proliferation responses, the number and phagocytosis of macrophage, serum hemolysin contents, the delayed type hypersensitivity response (DTH)of rats exposed to y -ray were measured 18h later, and TUNEL (TdT-mediated dUTP Nick End Labelling) and flow cytometry were used to investigate the effects of fucoidan on splenic lymphocyte apoptosis. Immunohistochemical technique was used to detect the expression of bcl-2 and bax. The relative immune indexes of model groups were obviously lower than those of the control. Fucoidan significantly modulated the function of immune system in irradiated rats and there was a dose-effect relationship within a certain range of dosage. The TUNEL and flow cytometry show that apoptosis ratio of splenic lymphocyte of the model groups were higher than those of the control.Fucoidan could markedly inhibit the effects of irradiation on apoptosis and the ratio of bcl-2/bax, and in a dose-effect manner. It was suggested that fucoidan could inhibit rat splenic lymphocyte apoptosis induced by irradiation, and its mechanism is associated with regulating the expression of bcl-2 and bax.111We want to study the influence and the possible mechanisms of fucoidan on tumor cells in vitro. We use the growth curve, MTT assay, Single cell gel electrophoresis assay (SCEG), agarose gel electrophoresis of DNA, TUNEL, flow cytometry and immunohistochemical staining, and K562 cell line was selected as target cell line. K562 were treated with fucoidan in different dosage (0.0, 0.5, 1.0, 2.0 and 3.0 mg/ml) for 24 h.The results were fucoidan could markedly inhibit the growth of K562 and induced DNA damages, and the effect of 1 mg/ml is the best. Agarose gel electrophoresis of treated groups showed typical "DNA ladder" and TUNEL positive cells were detectable. We could also detect apoptotic peaks by flow cytometry in model groups. The percentages of apoptosis cells were 3.98%, 9.56%, 29.86%, 20.96% and 12.98% in turn, and the best effect of fucoidan is 1 mg/ml. Inducing apoptosis in leukemia cells is the important anti-leukemia mechanism of fucoidan.The ratio of apoptosis relative gene Bcl-2/Bax is 2.22 > 1.15, 0.43, 0.69 and 1.02, and the best effect of fucoidan is also 1 mg/ml. It revealed that fucoidan perhaps through modulating the expression of Bcl-2 and Bax to induce apoptosis...