Evaluation Of The Biological Toxicity And Mechanism Of Sodium Oleate From The Angle Of BSA, Trypsin And Erythrocytes

Environmental pollution is one of the most important global problems at present. Surface active agent has the functions of scattering, emulsification and foaming because of its hydrophilic and oleophyllic properties, which has been widely used in every field of national product. Besides its convenience to our life, it damages the ecological environment, even threatens the survival and health of human. Surface active agent can interact with tissue fluid, cells or proteins when it enters into organism through respiratory tract inhalation, digestive tract intake and skin contact. However, when it arrives target organs, it will react with the materials, causing damage to the living tissues of organism. Therefore, it is essential to study the biological effect and mechanism of the anionic surfactant oleic acid sodium interacting with biological macromolecules and cells.Protein which almost paticipates in all metabolisms of organism is the physical basis of vital activities. Meanwhile, cell is the structural and functional unit of organism. The effects on cells and proteins from any pollutant may cause damage to their structures and functions, resulting in the functional disorder and diseases of organism. It will consequently be significant to learn the toxic effect of pollutants on vital bodies from molecular and cellular levels, illustrate the toxic mechanism of pollutants and fully evaluate the toxicity of pollutants.From the angle ofenvironmental toxicology, we have chosen BSA and trypsin as the target molecular and studied the toxic mechanism between sodium oleate and protein at the molecular level. At the cellular level, the experiment has chosen human erythrocytes as the target cells, and studied the influence of sodium oleate on GSH content of human erythrocytes.This study is mainly divided into five chapters as follows:Chapter one:Introductions of toxic evaluation methods, protein molecular and the main analysis technology are stated in this part. A brief literature review of the toxic interaction of surface active agent from the aspects of soil, water, aquatic creatures, terrestrial organism, and human body, etc., together with a prospective discussion about research direction is also presented.Chapter two:the structure and function information between sodium oleate and BSA was investigated using fluorescence spectroscopy, ultraviolet-visible (UV-Vis), circular dichroism (CD) spectroscopy and molecular docking under simulated physiological conditions. The results showed that sodium oleate can bound to BSA through hydrogen bond, at298K, the binding constant and binding site was respectively12.23×104Lmol-1and1.03, the UV-Vis and CD spectra found that the microenvironment polarity of BSA had been changed, the content of a-helix had reduced and the backbone chain of BSA had become looser. In addition, molecular docking result was corresponded to the spectra experiment.Chapter three:Multi-spectroscopic techniques and molecular docking methods were used to study the effect of sodium oleate to trypsin. It is found that sodium oleate can quench the intrinsic fluorescence of trypsin through static quenching, that a sodium oleate-trypsin complex was formed through hydrogen bond, and that the binding site and binding constant was1.08and3831.86L mol-1at295K. The microenvironment of trypsin was changed, the structure became looser, UV-Vis spectra and molecular docking result futher confirmed this conclusion.Chapter four:The toxicity of sodium oleate to human erythrocytes was investigated at the level of a single cell and the using of microfluidic chip single cell technology studied the effect of sodium oleate on glutathione in erythrocytes. The experiment results showed that with the concentration of sodium oleate increased, the GSH content of human erythrocytes gradually decreased, when the concentration of sodium oleate reached1.0×10-4mol/L, the GSH content dropped11.99%. The cell of high GSH content reduced while cells with lower GSH content began to appear, and the change of GSH content told us sodium oleate can cause a series of oxidative stress response of human erythrocytes.Finally, the author concluded the research parts and perspected the research and development direction. This study has studied the toxic mechanism between sodium oleate and protein cells with various research methods, and provided some references for the toxic mechanism of surface active agent toxicity at the same time.