Radioprotective Effects And Mechanism Of Astragaloside IV On The Liver Cell

Objective: The radiation protection effects and molecular mechanism of Astragaloside IV on the liver cell L-02 were explored to provide scientific data for developing of new radiation protection drugs.Methods: The experiment was divided into four groups, the control,the ASIV groups, the irradiation and the ASIV+irradiation groups. MTT method was used to detect the toxic effect of astragaloside IV on L-02 cells for selecting the suitable concentration, and test the cell viability of L-02 cells after irradiated with ?-rays to find appropriate irradiation dose from 0, 0.5, 1, 2, 4, 6, 8 Gy. MTT method was also used to detect the protection of astragaloside IV on irradiated L-02 cells. Clone formation assay and growth curves were used to observe the effects of astragaloside IV on clone formation and proliferative capability. WST-1 method,microplate test, and DCFH-DA method were used to detect SOD activity,GSH activity, MDA content, and ROS content, respectively. Meantime,the rate of apoptosis and cell cycle were detected by flow cytometry.Rhodamine123 fluorescent probe was used to detect the mitochondrial membrane potential altering in L-02 cell. ?H2AX foci were detected byimmunofluorescence confocal microscopy. The expression of Nrf2, HO-2,NQO1 proteins were observed by western blot method.Results:1. The results showed that astragaloside IV had no effect on the proliferation of L-02 cells when the concentrations were less than 80?g/mL. The cell viability decreased with the increasing absorbed doses and time after irradiation. Astragaloside IV could improve the proliferative capability of L-02 cells after irradiation and inhibit the increaseing of intracellular ROS and MDA contents caused by irradiation,as well as rejuvenate the intracellular SOD and GSH activities to some extent.2. The decreased apoptosis rate and the arrested cell cycle G2 had been effectively alleviated in correlating with the Astragaloside IV concentration after irradiation were indicated by flow-cytometry. A increased membrane potential correlating with the rise of Astragaloside IV concentration was observed by spectrophotofluorimetry after Rh123 dyeing.4. Confocal microscopy showed that the number of ?H2AX focus in Astragaloside+irradiation group was significantly less than the irradiation group.3. Western Blot results showed that: the expression of Nrf2, HO1-and NQO1 was increased in the irradiated cells, while, their expressionshowed the opposite trend in Astragaloside + irradiation group with increasing drug concentration.Conclusions:1. Ionizing radiation could decrease the survival rate of L-02 by inducing cell DNA damage, and G2 arrest.2. Astragaloside IV exhibited no significant cytotoxicities on L-02 cell within the concentration of 20-80 ?g/ml, and had a good effect of radiation protection.3. Astragaloside IV might play a role of radiation protection of reducing the oxidative injury induced by ?-rays by eliminating increased free radicals with in L-02 cells, increasing cell mitochondrial membrane potential, restoring antioxidant enzyme activity and alleviating G2/M arrest.4. Astragaloside IV exhibited its radioprotection via the activation of Nrf2 pathway in L-02 cell.