[Arrested proliferation and molecular mechanism of MAPKs' activations in manganese-treated PC12 cell line].
OBJECTIVE
We employed a model in vitro that used PC12 cell line to test the concentration and time dependent relationship of Mn-treatment as well as the characteristics of MAPKs pathway under the same conditions, to explore the Neurotoxicity mechanisms of manganese.


METHODS
PC12 cells in logarithm period incubated in culture media of 200, 400, 600, 800 micromol/L manganese (MnCl2) for 1 day, 2 days, 3 days, 4 days respectively. The neurotoxic concentration of manganese (MnCl2) on PC12 cells was screened by MTT and Plate clone forming tests. Cell growth curve was made in Typan-blue dying experiment. Western-blot was used to test p-Erk1/2 and p-p38.


RESULTS
MTT and plate clone tests showed that 200, 400, 600, 800 micromol/L MnCl2 could suppress the proliferation of PC12 cells in dose and time-dependent trend during 1 d, 2 d, 3 d, 4 d respectively. The cell inhibited ratio on the fourth day in 600 micromol/L MnCl2 culture medium approached 50% or more. Western-blot tests showed that p-Erk2 of PC12 cells incubated in 600 micromol/L MnCl2 culture medium was decreasing gradually on the 1st, 2nd, 3rd and 4th day and on the 2nd day less than control group by 75% (n = 3, P < 0.05). With cells treated by 200, 400, 600 micromol/L MnCl2 for 4 days, p-Erk2 lost by degrees. On the 4th day, p-Erk2 of 400 micromol/L MnCl2-treated group was less 78% than that of control group (n = 3, P < 0.05). P-p38 of PC12 cells incubated in 600 micromol/L MnCl2 culture medium was increasing gradually on the 1st, 2nd, 3rd and 4th day and on the 3rd day 6.6 times higher than that of control group (n = 3, P < 0.05). P-p38 of PC12 cells enhanced by degrees in 200, 400, 600 micromol/L MnCl2 treated for 4 days and in 400 micromol/L MnCl2 treated group on the 4th day was 4.7 times higher than that of control group (n = 3, P < 0.05).


CONCLUSIONS
The decreased p-Erk2 and the increased p-p38 maybe co-worked to induce proliferation arrest and apoptosis in PC12 cells.
Xu
Wen
W
Department of Occupational and Environmental Health Science, the Fourth Military Medical University, Xi'an 710032, China.
Chen
Jingyuan
J
Wang
Feng
F
Chen
Yaoming
Y
Zhao
Fang
F
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008345:Manganese / Q000009:adverse effects*; D016716:PC12 Cells; D051381:Rats; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D008345:Manganese; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases