| BackgroundRadiotherapy plays an important role in the treatment of malignant neoplasm,such as skin cancer,nasopharyngeal cancer,breast cancer and lymphoma et al. In order to improve efficacy of treatment and survival quality of patients,radiotherapy,as one of combination treatment,is often combined with chemotherapy,surgery,biotherapy and traditional Chinese medicine. In fact,radiotherapy involves a balance between the minimizing normal tissues damage and maximizing tumor eradication. But it is difficult to do so in clinical trial. On the contrary,it gives arise to complication of normal tissues. Recently,with the development of health cares and nuclear industry,the acute and chronic radical symptoms,which have burn of local skin,decline of immune function,mutation of gene and et al,occurred to employer enjoying in radical industry because of exposure to low dose of ionizing irradiation and occasional nuclear incidence. Therefore,it is necessary to radioprotection medicine that studies the mechanisms of radiation induced damage and find a new kind of radioprotector with valid efficacy and minimal side effects.Coenzyme NADH involves in energy metabolism and transportation of nucleic acid,proteins and carbohydrates. NADH quinone oxidoreductase 1 (NQO1) is a ubiquitous cytosolic flavoenzyme that catalyzes two-electron reduction of various quinones,with NADH or NADPH as an electron donor. This NQO1-mediated reduction mechanism is responsible for the cellular defense against various damaging quinines. It is reported that NADH can inhibit production of cellular reactive oxygen species,decline potential of mitochondria. Devoid of NADH in Nerve cell results in denaturalization and necrosis,which is associated with Alzheimer'diseae. The content of cellular NADH declines after irradiation,can give arise to inactivity of PARP enzymeand decline of DNA repair ability. NADH not only can increase creation of Dopamine neurotransmitters,but also alleviate symptom of Parkinson' disease. At the same time,the decreasing of cellular NADH content,after UV irradiation,may be associated with development of skin cancer. In addition,NADH can rescue cell damage induced by rotenone and regulate bcl-2,p53 and bax gene expression. Therefore,it is a new consideration and method to explore a new kind of radioprotector by drug modification or regulation of radiation induced damage.ObjectiveStudying cellular morphological change,signal transduction of apoptosis,metabolic production and mitochondria regulation,we intended to explain the mechanisms of NADH against radiation-induced damage in vitro. In vivo,observing change of haematopoietic system and immune organs in Co60 Y ray radiated mice,we shall study ability of NADH against irradiation induced damage and explore a new kind of radioprotector in order to decrease the complication of normal tissues damaged by radiotherapy or non-medical irradiation.Methods1. MTT colorimetric assay was applied to detect X-ray induced damage in human liver cell line L02,as well as effect of NADH against growth inhibition of irradiated L02 cells. Percent apoptosis was determined by flow cytometry. Apoptotic change was observed by Tunnel dyeing methods. Untrastructure of hepatocyte was also observed by transmission and scan electron microscope.2. Positive rate of signal transductional molecules,p53,p21,p!6,bax and bcl-2 proteins expression as well as phrase of cycle and cycle-regulated proteins,was determined by flow cytometry. Lasers scanning confocal microscope was employed to detect intracellular free Ca2+ value withFlu-3-AM,pH value with probe SNARF-1-AM and ROS value with probe H2DCF in L02 cells. The activity alteration of Caspase 3 and PART cleavage was detected by SDS-PAGE electrophoresis and western-blotting methods. The mRNA expression of p53 and bax gene were analyzed by RT-PCR.3. By isolating mononuclear cells of peripheral blood in healthy individual and stained with FITC or PE-labeled monoclonal antibodies,we determined positive rate of lymphocytes subs...
|
PDF Full Text Request