Abstract: The invention discloses a method for screening a therapeutic target of acute radiation-induced gastrointestinal syndrome and use of TIGAR target in the preparation of a medicine for treating radiation-induced gastrointestinal syndrome. The CreERT-loxP transgenic mouse model is used, in which quiescent intestinal crypt stem cells are effectively promoted to proliferate after exposure to high-dose ionizing radiation, to screen a therapeutic target that still has a therapeutic effect for radiation-induced gastrointestinal syndrome 18-24 h after ionizing radiation. Gene splicing occurs in particular cells in the CreERT-loxP transgenic mice only after the injection of tamoxifen, thereby regulating gene expression. The actual situation of initial exposure and then treatment after a nuclear accident is well simulated, so the invention is of great practical significance.

Abstract: The present invention relates to a method for constructing a nanodrug with adhesion in small intestine, including activating a basic amino acid with a small molecular catalyst, adding a polysaccharide solution and reacting to obtain an amphiphilic polymer; then adding a drug solution and mixing uniformly, to obtain drug-loaded nanoparticles including a hydrophilic portion that is the basic amino acid and a hydrophobic portion that is the polysaccharide and drug, wherein the drug has radioprotective effect or can inhibit ionizing radiation-induced cell death; and adding the drug-loaded nanoparticles to a dopamine solution to obtain a nanodrug including the basic amino acid and polydopamine on the surface after the reaction. The present invention provides an oral nanodrug with adhesion in intestinal tract, and the nanodrug has good biocompatibility, adhesion in small intestine and mucus barrier penetration ability, and can withstand the acid and alkali environment in the gastrointestinal tract.

Abstract: The invention discloses a method for determining the repair activity of NHEJ. In this method, HPRT gene is mutated by using a site-directed gene mutation technology, and plasmid transfection, and 6-TG treatment are performed. By means of the method of the invention, the NHEJ repair activity level of cells can be observed by measuring the cell viability. The method can be used for screening the effects of different drugs and different genes on the NHEJ repair activity.

Abstract: The invention discloses a method for determining the repair activity of NHEJ. In this method, HPRT gene is mutated by using a site-directed gene mutation technology, and plasmid transfection, and 6-TG treatment are performed. By means of the method of the invention, the NHEJ repair activity level of cells can be observed by measuring the cell viability. The method can be used for screening the effects of different drugs and different genes on the NHEJ repair activity.