Effects of enriched environment and impoverished environment on learning and memory ability of manganese-exposed mice / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of enriched environment and impoverished environment on the learning and memory ability of manganese-exposed mice and the mechanism.</p><p><b>METHODS</b>Forty female Kunming mice were randomly and equally divided into 4 group: control group (CG), standard environment and manganese exposure group (SEG), enriched environment and manganese exposure group (EEG), and impoverished environment and manganese exposure group (IEG). The mouse model of manganese poisoning was established by intraperitoneal injection of manganese chloride. The learning and memory ability was tested by Morris water maze. The expression of cAMP response element-binding protein (CREB) in area CA1 of the hippocampus was measured by immunohistochemistry.</p><p><b>RESULTS</b>In place navigation test, the SEG had a significantly longer escape latency than the CG (P < 0.05), and the EEG had a significantly shorter escape latency than the SEG (P < 0.05); there was no significant difference in escape latency between IEG and SEG (P > 0.05). In spatial probe test, the EEG had a significantly greater number of platform crossings than the SEG (P < 0.05), and the IEG had a significantly smaller number of platform crossings than the SEG (P < 0.05). The expression of CREB in area CA1 of the hippocampus was significantly lower in IEG and SEG than in CG (P < 0.05), and it was significantly higher in EEG than in SEG (P < 0.05).</p><p><b>CONCLUSION</b>In the enriched environment, the learning and memory ability of manganese-exposed mice can be improved, which may be due to the increased expression of CREB in the hippocampus.</p>

Effect of Lycium barbarum polysaccharides on neurogenesis and learning & memory in manganese poisoning mice / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effect of Lycium barbarum polysaccharides (LBP) on neurogenesis and learning & memory of manganese poisoning mice.</p><p><b>METHODS</b>Healthy adult Kunming mice were divided into 5 groups, the control group (A), the manganese poisoning (by manganese chloride peritoneal injection) group (B), the manganese poisoning and treated with gastric perfusion of high, medium, low dosage LBP groups (C, D and E). The spatial learning & memory capacity of mouse was determined by Morris water maze training test. The neurogenetic cells were labelled with bromodeoxyuridine (BrdU) and detected by immunohistochemistry.</p><p><b>RESULTS</b>The average escape latency was significantly higher and the times of passing through platform lower in group B than those in group A (P<0.05). BrdU positive cells in groups C, D and E were significantly more than those in group B (P<0.05).</p><p><b>CONCLUSION</b>LBP could enhance the learning & memory capability of the manganese poisoning mice by promoting neurogenesis in hippocampus.</p>

Effects of manganismus on proliferation of neural stem cells in mice's hippocampus / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effects of manganese poisoning on the proliferation of neural stem cells (NSCs) in mice's hippocampus.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>1) 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).</p><p><b>CONCLUSIONS</b>Manganismus can affect the ability of learning and memory, which is probably caused by the inhalation of manganese on NSCs in hippocampus.</p>