The Protective Effect Of Ultra-small Nanoclusters Au-MoS₂ On Radiation Oxidative Damage And The Effect Of Radiation On The MC3T3-E1 Cells Of RNAi NICD

As is known,high-energy radiation produced in excessive amount of ROS and these excessive free radicals can inevitably cause the oxidative stress.The accumulated ROS after radiation could damage the normal tissues by causing DNA strand breaks and lipid peroxidation,leading to cell dysfunction and even death.Therefore,scavenging the excessive harmful ROS is essential for radioprotection.In recent years,catalytic nanomaterials have shown great potentials in antioxidant activities and radiation protection effects.It was found that the catalytic behaviors of the nanomaterials are positively correlated with their radioprotective effects.Thus,enhancement of catalytic activities is key for optimal radioprotective effects.In fact,enhanced catalytic activities from intercalation of metallic atoms have already been reported in recent years.It was also reported that Au-MnO2,Al2O3-Au,Au-Pt and Au-TiO2 hybrid systems show the enhancement of catalytic activities.We have previously developed catalytic nanomaterials such as MoS2,which could prevent hazardous radiation-induced damages in vitro and in vivo.In this work,we employed a solvothermal method to hybridize ultrasonically exfoliated MoS2 nanomaterial with gold clusters(Au-NCs)to form ultrasmall Au-MoS2 clusters with enhanced catalytic activity.Preliminary electrochemical experiments showed that compared with Cys-MoS2,the as-prepared Au-MoS2 clusters showed remarkable catalytic properties in decomposing H2O2 through enhanced oxygen reduction reactions.In vitro studies indicated that Au-MoS2 offers better scavenging activities for radiation-induced excessive ROS than Cys-MoS2.Moreover,Au-MoS2 could protect the bone marrow hematopoietic system from high energy radiation by increasing the number of bone marrow nucleated cells and improving the DNA level significantly.Catalytic material Au-MoS2 has the potential to improve the radiation protect effects.Using shRNA interference(RNAi)inhibits NICD expression in MC3T3-E1 cells to observe effect of inhibited the NICD expression on their cells proliferation and function-related genes expression in MC3T3-E1 cells exposed to radiation.Establish the inhibited NICD MC3T3-E1 cells and detect cells' NICD expression by qRT-PCR and Western Blot.MC3T3-E1 and inhibited NICD MC3T3-E1 cells are irradiated by 2 Gy and method of BrdU coroperation and qRT-PCR usded to detect their proliferation and function-related genes expression.The expression of NICD in MC3T3-E1 cells could be inhibited by the RNAi technology.The Inhibition of NICD expression can interfere the proliferation of precursors osteoblasts and osteoblasts.After 2 Gy radiated,the proliferation of precursor,osteoblast and NICD RNAi osteoblast decreased significantly,and the function-related genes expression of each target cells are as follows.?After 2 Gy radiated,the expression of Runx2 were up-regulated in precursors osteoblasts,down-regulated in NICD RNAi precursors osteoblasts.?After 2 Gy radiated,the expression of ALP in precursor osteoblasts,osteoblasts and NICD RNAi precursors osteoblast were up-regulated,and was down-regulated in NICD RNAi osteoblasts.?After 2 Gy radiated,the expression of RANKL in precursor osteoblasts was down-regulated,and was up-regulated in osteoblasts and NICD RNAi precursors osteoblast,while inhibiting the NICD'expression could cause the opposite change in other cells.?After 2 Gy radiated,the expression of OPG were down-regulated in precursors osteoblasts and osteoblasts,inhibiting the NICD'expression could cause expression up-regulation in precursors osteoblasts and down-regulation in osteoblasts.?After 2 Gy radiated,the expression of M-CSF in the target cells shown the same trend as the expression of RANKL.In conclusion,the inhibition of the NICD expression exerts different effects on the differentiation of irradiated osteoblasts.The inhibition of the NICD expression could cause a series of changes including:?It may decrease the proliferation of precursor osteoblasts and osteoblasts and protect the proliferation of differentiating precursor osteoblasts after irradiation.?It can significantly inhibit the differentiation of precursors osteoblasts after irradiation and reduce bone loss through regulating the expression of Runx2.?The osteoblasts did not show the regulated function of the osteoclasts through the RANKL/OPG/RANK system.?The osteoblasts can exhibit the inhibited function of the osteoclasts through the expression of M-CSF.