The Effect Of P38Promote Mitogen-activated Protein Kinase In Potassium Dichromate Induced Apoptosis Of A549Cells

Chromium(Cr) as a common chemical elements, the valence state is from-2to6,+3and+6is common. Among them, the trivalent chromium is non-toxic in the effective dose, and it is humans and animals essential nutrients. The hexavalent chromium is a toxic agent, has carcinogenicity, mutagenicity, teratogenicity, immunotoxicity, reproductive toxicity, neurotoxicity, is a heavy metal environmental pollutants.Hexavalent chromium is widely present in cigarrtte smoke, car exhaust and living environment, Used principally in the electroplating industry, leather industry, chemical industry, dyestuff industry, metallurgical industry, as well as stainless steel welding and wood processing industries, etc. Hexavalent chromium can restore the system to restore the cells, and thus produce large amounts of low valence chromium ions, low valence chromium ions easily bind to DNA to produce DNA adducts; Chrome will produce large amounts of reactive oxygen species in the process of resore, and then induced cellular oxidative stress response, leading to direct damage of cellular DNA and long-term damage of cell repair system, reactive oxygen species produce a series of signal transduction cascade reaction on cell stimulation. Experiments show that hexavalent chromium can affect apoptosis signaling pathways. P38-MAPK can be activated by a variety of growth factors, inflammatory cytokines and a variety of physical and chemical stimuli, Activated P38kinase can regulate cell growth, differentiation, apoptosis, thereby affecting the downstream pathway. Cysteine aspartic acid proteolytic enzymes-3plays an important role in apoptosis,and plays a central factor in the process of Caspase protease cascade cutting. In recent years, P38-MAPK and Caspase-3as an important factor of the hot issues of mediated cell proliferation and apoptosis, etc.Objective:Based on the above analysis, through the establishment of in vitro cell model in this study, cultured human lung epithelial cells (A549cells), then make it expose to different concentrations of potassium dichromate dye venom, observe the level of apoptosis rate each packet, and analysis of expression level of phosphorylation of P38activated by the potassium dichromate on A549cells, total P38, caspase-3and other apoptotic proteins in the protein expression level. Then explore the potassium dichromate-induced A549cell apoptosis mechanism, provide a theoretical basis to further understand the mechanism of potassium dichromate induced lung cancer.Method:1. Firstly, eatablish the model of the A549cells in vitro.2. MTT assay to determine the effection on A549cells growing of different concentration of potessium dichromate chromium, and determine the appropriate exposure concertration.3. Flow cytometry to detecte the effection of Potassium dichromate to the apoptosis of A549cells, then observed the expression levels of apoptosis rate of individual groups and inhibitors group which joining the P38inhibitor.4. Western bloting were using to detect the expression levels of P38, p-P38, and caspase-3, which were exposed to potassium dichromate.5. Statistical analysis. SPSS12.0statistical software was used, the data was measured by and t-test, ANOVA analysis (analysis of variance, ANOVA), the data for statistical analysis (inspection level α=0.05).Results:1. MTT results:exposure concentration40μmol/L, the inhibition of proliferation of A549cells was76.25%. Depending on the cell activity in the cells after exposure to determine the IC50=7.6μmol/L, Selection of exposure concentrations of0μmol/L,2.5μmol/L,5μmol/L,10μmol/L, step experiment.2. Flow cytometry result:when potassium dichromate exposure concentration of0μmol/L, compared to the normal exposure groups, early apoptosis rate of group A and inhibitor exposure group I, Group B, the difference was no statistically significant (P>0.05). When exposed to concentrations of potassium dichromate of2.5μmol/L,5μmol/L and10μmol/L, compared to the normal exposure groups, early apoptosis rate of group A and inhibitor exposure group I, Group B, the difference was statistically significant (P<0.05).3. protein express result:Normal potassium dichromate exposure group of P-P38 protein and Caspase-3protein relative expression level compared to the potassium dichromate inhibitors group of P-P38protein and Caspase-3protein relative expression level, the difference was statistically significant (P<0.001); Each grouping cells P38protein under different stimuli, the difference was not statistically significant (P>0.05).Conclusion:Potassium dichromate can induce apoptosis of A549cells, display dose-response relationship. P38signaling pathways appear regulation action in potassium dichromate induced apoptosis of A549cells, SB203580can inhibit P38signal transduction pathways, play a protective role in A549cells apoptosis.