Relationship between apoptosis and molecular mechanism of p-38 MAPKS activation in manganese-treated PC12 cells

Objective To employ PC12 cell line as a model in vitro to test the concentration and time of maganese on proliferation arrest,and to o bserve the changes of cell morphology,cell cycle and biochemical marker and furt her to study the relationships between above aspects and activiations of p38MAPK s pathway.PC cells in logarithm period incubated in culture media with 200,400,600,800?μmol /L manganese (MnCl 2) for 1,2,3,4 days respectively.Methods Cell viability was examined by MTT.Cell cycle was m onitored by FCM (flow cytometry).Morphological changes of PC12 cells was investi gated by transmisssion electron microscope.Agarose gel electrophoresis was used to test the genomic DNA. Western-blot was used to test p-p38.Results MTT revealed that 200,400,600,800?μmol/L MnCl 2 could suppress the proliferation of PC12 cells in dose and time-dependent tren d.The cell inhibited ratio on the fourth day in 600?μmol/L MnCl 2 approached 50% or more.FCM showed that the cell cycle of the PC12 cells could be inhibite d in S period at the concentration of 600?μmol/L MnCl 2 on the 4th day and ap optosis was observed through FCM and transmisssion electron microscope Biochem ical hallmark of DNA fragments was observed.Western-blot tests showed the p-p38 in 6 00?μmol/L MnCl 2 culture medium was increasing gradually on the 1st,2nd,3rd a nd 4th day.the p-p38 on the 3rd day was 6.6 times higher than that of control group (n=3,P0.05).The p-p38 was enhanced by degrees in 200,400,600?μ mol/ L MnCl 2-treated PC12 cells in 4 days.The p-p38 of 400?μmol/L MnCl 2 treated group on the 4th day was 4.7 times higher than that of control group (n=3, P0.05).Conclusion Manganese upregulated p-p38 through MEK3/6 dow nstream to induce proliferation arrest and apoptotic cell death.