· 초록제출 예시

Sulfated polysaccharide isolated from Ecklonia cava attenuates radiation-induced immune suppression

So Jin Bing1, Ginnae Ahn2, Danbee Ha1, Sungwon Kim1, Jaehak Im1, Subin An1, Jinhee Jo1, You-Jin Jeon2, Youngheun Jee1*

1College of Veterinary Medicine and Applied Radiological Science Research Institute, Jeju National University, Jeju 690-756, South Korea
2 Faculty of Marine Life Science, Jeju National University, Jeju 690-756, South Korea

Exposure to gamma ray irradiation inhibits cell survival and proliferation by causing DNA damage via the production of ROS and subsequent oxidative stress. Previous studies have reported that Ecklonia cava (Alariaceae, Phaeophyta) containing plentiful polysaccharide has the beneficial capacity for antioxidant, immunomodulation and immune activation. Present study investigated whether sulfated polysaccharide (SP) of E. cava containing high content of fucose and sulfate group has possible impact on radiation-induced tissue damage reduction and, if effective, its underlying mechanism. SP significantly stimulated the survival and proliferation of splenocytes, a highly radio-sensitive immune cell, after an exposure to 2 Gy irradiation. In addition, SP treatment significantly reduced the ROS production from gamma ray irradiation. DNA damages such as tail DNA percentage (%) and olive tail DNA movement (um) and the formation of apoptotic sub-G1 hypodiploid cells from gamma ray irradiation were markedly decreased by treatment of SP in splenocytes. Furthermore, SP enhanced proliferation and differentiation of CD3+ mature T cells and CD45R/B220+ pan B cells in spleen. Expression and production of interleukin (IL)-2 and immunoglobulin (Ig) G1 and 2a were markedly increased by SP treatment, compared to those in non-treated cells. Also, SP led to the activation of NFkB pathway, a downstream of JNK pathway, by inducing the phosphorylation of IkBa, translocation of NFkB p65 into nucleus, and its DNA binding activity. Interestingly, the application of NFkB inhibitors such as TPCK and PDTC along with SP decreased the proliferation of lymphocytes as the activation of NFkB was markedly blocked by the reduction of SP-mediated IL-2 production. In conclusion, this research demonstrates that the immune activation capacity of murine lymphocytes by inducing IL-2 production via the JNK/NFkB pathways contributed to the protection of radiosensitive immune cells against oxidative damages caused by gamma ray irradiation.

Acknowledgements: This research was supported by Technology Development Program for Fisheries, Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea (110088031HD110).