Effects Of Plasma On The Apoptosis Of HepG2 Cells And The Differentiation Of Neural Stem Cells

Atmospheric Pressure Room Temperature Plasma Jets(APRTP-Js) has many advantages, such as low-cost, flexible and rich in chemically active particles. In the meantime, due to the plasma temperature about 300 K close to room temperature that make it suitable for heat-sensitive instruments or biological materials such as endoscopes, cells and tissues. Therefore, APRTP-Js has a great prospect in biomedical application.Although the scale of micro-plasma is restricted within a millimeter, it still has the characteristics of conventional plasma,such as being able to release different chemically active particles including reactive oxygen species(ROS) and reactive nitrogen species(RNS). Since the micro-plasma can work at atmospheric pressure and its temperature is close to room temperature, it can avoid thermal and electric field which can cause damage to the biological material. In addition, the micro-plasma positioning accuracy is better, and it can operate on a single cell.The treatments of cancer and neurological diseases have become the hot topic of the current medical research. Cancer mortality, after cardiovascular disease, is the second largest cause of death in the disease. Presently, there are some conventional methods for cancer treating, such as radiotherapy, chemotherapy and surgical therapy, but these methods have significant by-side effects. Neurological disease has caused a great threat on the life quality of human-being. So far, some methods can be used to treat neurological disorders, such as transplantation therapy, gene therapy and drug therapy. However, these methods have some insufficients. Therefore, exploring new ways to treat cancer and neurological diseases have been becoming a hot research.The present study aims at achieving effective regulation of plasma-induced apoptosis in cancer cells on the single cell level and neural stem cell differentiation. Meanwhile, the underlying mechanisms of plasma interaction with neural stem cells were also investigated.The main results were as follows:(1) The relationships between the micro-plasma treatment and HepG2 cell apoptosis.By reducing the diameter of the microelectrode tip to 1-2 μm, accurate treatment of cells at single cell level was achieved. Results indicated that micro-plasma treatment had lesscellular toxicity on the normal liver cells L-02, which is the necessary basis for clinical application of micro-plasma, while can induce apoptosis in HepG2, which provides theoretical support for the biomedical application of micro-plasma.(2) The relationships between ROS, RNS and micro-plasma-induced apoptosis of HepG2. Chemically active particles of plasma were analyzed using spectrometer and it was found that the major particles of plasma includes reactive oxygen species(ROS) and reactive nitrogen species(RNS). The wax-coated(micro-plasma) and none-wax-coated(no micro-plasma) microelectrodes were used to treat four HepG2 cells randomly. It was found that the HepG2 cells treated with no-wax-coated microelectrodes appeared apoptosis, therefore, it can be concluded that the chemically active particles produced by micro-plasma was the inducer of apoptosis in HepG2 cells.(3) Effective control of C17.2-NSCs differentiation was achieved through APRTP-Js treatment. First, the discharge parameters of APRTP-Js was optimized; Then, plasma energy density that had no cytotoxicity to C17.2-NSCs was determined by MTT assay.Meanwhile, the plasma dose were adjusted to regulate the differentiation of C17.2-NSCs.Results showed that 60 s of plasma treatment could effectively promote the differentiation of C17.2-NSCs to neurons.(4) Differentiation of C17.2-NSCs was studied. First, the plasma emission spectrometer at 275-290 nm wavelength spectrum was analyzed, it was found that the main active ingredient was NO. Results showed that plasma treatment can lead to the increase of NO concentrations in the extracellular medium and induce intracellular iNOS expression in C17.2-NSCs. All of the results indicated that NO was involved in the plasma-regulated C17.2-NSCs differentiation.(5) The mechanisms underlying the process of plasma-regulated C17.2-NSCs differentiation was studied: Western Blot and ELISA results showed that the overall trend of the expression of NGF, BDNF and GDNF were up-regulated. All the evidence indicated that the plasma treatment promoted the differentiation of C17.2-NSCs into neurons.