Effect And Mechanism Of Madecassoside Against Damage Induced By Radiation In Vitro And In Vivo

Objective: To investigate the anti-irradiation effect and mechanism of madecassosidein vitro and in vivo.Methods:①NIH3T3cells were cultured. Before the radiation, the cells were trettedwith MC in different concentration respectively. The irradiation damage models of cellswere established by60Co gamma ray (15.0Gy, at a dose rate of2.0Gy/min), then the effectof MC on those cells were determined by MTT assay. The pyrogallol auto－oxidationproduced superoxide anion (O2·), and the scavenging rate on the free radicals of MC wasdetermined by microplate retder.Total SOD activity dectection kit (NBT method) was usedto detect the level of SOD in the cells lysate after the radiation. By flow cytometry, cellcycle and cell apoptosis kits were used to detect the effect of MC with differentconcentrations or at different time points (36h,60h) after radiation.②Irradiation damagemodels of Kunming mice were established by X ray (10.0Gy, at a dose of1.67Gy/min) invivo. The protective effect of MC against damage of irradiation were observed through theweight，spleen and thymus indexes of mice; Splenocyte proliferation was determined byMTT assay; Protective effect of MC against small intestine damage of irradiation wasobserved through hematoxylin and eosin (HE) staining.Results:①To NIH3T3cells, both three concentrations of MC（15μg/mL,7.5μg/mL,3.75μg/mL）have the protective effect but this protective effect does’t emerge at1.88μg/mL.The O2-radical scavenging rate of MC retch44%at2.0mg/mL, but this scavenging rate islow than the positive control-ascorbic acid (VC)(74%) at the same concentration.120μg/mL,60μg/mL,30μg/mL of MC could significatly incretse the level of SOD in thecell lysate, but MC doesn’t elevate this level at the concentration of15μg/mL.48hoursafter irradiation, compared with the model group cells, MC(7.5μg/mL,3.75μg/mL) canmake S phase prolonge, G2phase and SubG1phase duration decretse, and it’s opportunefrom S phase to G2phase, so the whole result is that MC alleviates the cell cycle arrest.24 hours,48hours after the iaradiation, compared with the model group,15μg/mL of MC canreverse radiation-induced apoptosis and recover the cells’normal state.②Nine days afterirradiation, MC fails to stop the decline in body weight in mice induced by irradiation, andon the eight day after the irradiation MC can improve the most irradiation mice spleenindex and thymus index. MC large dose group (25mg/kg) can improve the spleenlymphocyte proliferation activity. On the morphological observation, MC can make theintestinal epithelium organizational structure of the mice tend to complete after irradiation(5hours, the second day and the eight day).Conclusion: MC has an obvious anti-radiation effect. Anti-oxidant, preventing cellapoptosis and improving the immune response of mice may be involved.