OBJECTIVETo explore the effects of manganese poisoning on the proliferation of neural stem cells (NSCs) in mice's hippocampus.

METHODSThe mice (weight 8 approximately 10 g) were divided into control group(CG) low-dose group(LDG) middle-dose group(MDG) and high-dose group(HDG)by intraperitoneal injection of 0, 5, 20, 50 mg x kg(-1) x d(-1) of manganese chloride dissolved in physiological saline. The ability of learning and memory was detected by Morris Water Maze, and the proliferation of NSCs in subgranular zone (SGZ) in these mice's hippocampus was also detected by immunohistochemistry.

RESULTS1) Compared with the CG, the ability of learning and memory in all manganism group decreased significantly (P < 0.01) and this phenomenon in HDG was most notable (P < 0.01). Meanwhile, the ability of memory was negatively correlated with the dose of manganese chloride (r(s) = -0.598, P < 0.01), but the difference of swimming speed in every group was of no statistic significance. (2) The numbers of NSCs in proliferation period in SGZ of all manganism groups was much lower than that of CG (P < 0.01) negatively correlated with the dose of manganese chloride (r(s) = -0.666, P < 0.01). (3) The reduction of NSCs had a positive correlation to the depression of learning and memory (r(s) = 0.734, P < 0.01).

CONCLUSIONSManganismus can affect the ability of learning and memory, which is probably caused by the inhalation of manganese on NSCs in hippocampus.