Effects Of Plasma On HepG2Cell Apoptosis And Neural Stem Cell Differentiation

In recent years, research on plasma medicine has become a hot topic. Atmospheric Pressure Room Temperature Plasma Jets (APRTP-Js) have great potential in biomedical application, it is due to:(1) the temperature of plasma is close to room temperature;(2) plasma can be generated in an open air, thus avoiding the restrict of object to be treated. Currently, the application of plasma has made many progresses in sterilization, skin disease treatment, oral clinic, blood coagulation and cancer treatment, etc. Research showed that the effects of plasma are mainly mediated by the interacting of organism with active ingredients generated by plasma, including free radicals, charged particles, ultraviolet, excited particles, etc. The active ingredients in the plasma can be controled through adjusting plasma parameters and dose, thus plasma can have potential applications.Cancer treatment and recovery of nervous system are the most challenging problems in medical research. About8million people die of cancer each year, ranking second only after the heart disease. Neurological diseases, including brain trauma, spinal cord injury, crania-cerebral, Alzheimer’s and Parkinson’s diseases, mainly effect by functional disruption of feelings, motions, consciousness and vegetative nervous systems which can influence the quality of people’s life. Therefore, exploring new methods of cancer treatment and recovery of nervous system has become a hot topic. The goal of the research is to realize effective apoptosis induction in cancer cells and regulation of neural stem cells differentiation, through adjusting the plasma parameters and dose. It may provide insight into effective strategy to regulating cancer cell apoptosis and nerve reconstruction. Meanwhile, the underlying mechanism of interaction between plasma and cells is also explored. The major results are as follows:1) Through adjusting the plasma parameters and dose, apoptosis were effectively induced in human hepatocellular carcinoma HepG2cells. While, relatively low sensitivity to plasma was found in normal liver cells (L-02), indicating the sensitive selectivity of plasma between HepG2cells and L-02cells.2) The relationship between oxidative/nitrative stress and plasma-induced apoptosis in HepG2cells was studied and the results suggested that ROS/RNS, which facilitated oxidative and nitrative stress in cells, played a causative role in plasma-induced apoptosis in HepG2cells.3) The relationship between endoplasmic reticulum stress (ER stress) and plasma-induced apoptosis in HepG2cells was investigated. It was found that intracellular calcium homeostasis was disturbed along with the occurrence of ER stress in plasma-treated HepG2cells. The process of ER stress-induced apoptosis was mediated by the downstream caspase12cascade and CHOP.4) Through adjusting the plasma parameters and dose, energy density of plasma being noncytotoxic to C17.2-NSCs was determined and results showed that plasma-treated time should be less than150s each well in12-well plate. The effective regulation of C17.2-NSCs differentiation using plasma was realized under the above-mentioned conditions. Plasma treatment (60s) significantly promoted the differentiation of C17.2-NSCs into neurons (the differentiation rate was nearly75%), and the maturity of the morphological structure of neurons is increased significantly, including more dendritic branchings, larger dendritic areas and longer neurites. The identification of neuronal fate showed that mostly cholinergic and motor neuronal progenies produced under the plasma treatments.5) The possible role of nitric oxide in the plasma-induced C17.2-NSCs differentiation was explored and it was found that plasma increased NO concentration in culture medium and iNOS expression. These effects could be attenuated by NO scavenger (Hemoglobin, Hgb), indicating that plasma-generated NO is indeed important factor involved in C17.2-NSCs differentiation.6) The possible signaling pathways involved in plasma-induced C17.2-NSCs differentiation was examined, and it was found that NO promoted the differen-tiation of C17.2-NSCs into neurons mainly through regulating the downstream effector of Notch and bHLH signaling.7) The effects of plasma on primary rat neural stem cells (NSCs) were assessed. The results showed that the plasma could promote the differentiation of rat NSCs into neurons, which was characterized by increased neuronal differentiation rate, more branchings and longer neurites. These results suggested that the effects of plasma may be generic and applicable to other neural stem cells.