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目的探讨锰中毒对小鼠大脑海马区神经干细胞增殖状况的影响。方法将体重为8～10g的28只昆明种小鼠分为生理盐水对照组和低、中、高剂量3个染毒组每组7只,通过腹腔注射氯化锰染毒,染毒剂量分别为5、20、50mg/kg,用Moms水迷宫检测其学习记忆能力情况,以免疫组化方法检测其大脑海马结构的齿状回颗粒下区(SGZ)神经发生情况。结果(1)与对照组比较,各染毒组小鼠的学习和空间记忆能力明显降低,差异有统计学意义(P<0.01),以高剂量组最为明显;同时,记忆能力与染毒剂量呈负相关(r_s=-0.598,P<0.01),而各组小鼠游泳速度的差异无统计学意义(P>0.05);(2)各染毒组小鼠的齿状回颗粒下区内5-溴代脱氧尿嘧啶核苷(BrdU)阳性细胞平均数目均比对照组明显降低,差异有统计学意义(P<0.01),且随剂量加大而减少,与中毒剂量呈负相关(r_s=-0.666,P<0.01);(3)空间记忆能力的减退和SGZ内BrdU阳性细胞平均数目减少之间呈正相关(r_s=0.734,P<0.01)。结论幼年小鼠接触锰可影响其学习记忆能力,其机制可能与抑制海马结构的神经干细胞增殖有关。
Objective To investigate the effect of manganese poisoning on the proliferation of neural stem cells in the hippocampus of mice. Methods 28 Kunming mice weighing 8 ~ 10g were divided into saline control group and low, medium and high doses of three exposure groups of 7 mice in each group. The rats were injected intraperitoneally with manganese chloride, 5,20 and 50 mg / kg respectively. Moms water maze was used to detect the learning and memory abilities. The neurogenesis of the dentate gyrus subgranules (SGZ) in the hippocampus was detected by immunohistochemistry. Results (1) Compared with the control group, the learning and spatial memory abilities of mice in each exposure group were significantly decreased (P <0.01), especially in the high-dose group. At the same time, the memory and exposure dose (R_s = -0.598, P <0.01), while there was no significant difference in swimming speed of mice in each group (P> 0.05); (2) BrdU positive cells were significantly lower than those of the control group (P <0.01), and decreased with the increase of dose, but negatively correlated with the dose of poisoning (r_s = -0.666, P <0.01). (3) There was a positive correlation between the decrease of spatial memory capacity and the average number of BrdU positive cells in SGZ (r_s = 0.734, P <0.01). Conclusion Exposure of young mice to manganese can influence their learning and memory ability, which may be related to the proliferation of neural stem cells that inhibit hippocampal formation.