Cuprizone致小鼠脱髓鞘对胼胝体少突胶质细胞数及动物运动能力的影响

目的研究Cuprizone(CPZ)诱导C57BL/6小鼠脱髓鞘对胼胝体少突胶质细胞变化情况,并探讨对小鼠运动能力的调控特点。方法以正常饲料喂食的6周龄雄性小鼠作为对照,实验组用含0.2%Cuprizone的混合饲料持续喂食6周龄雄性小鼠6周,诱导中枢神经系统脱髓鞘。用LFB组化和MBP免疫组化技术鉴定脑胼胝体区的脱髓鞘改变,确认模型的稳定可靠性。结合MBP和CC-1免疫荧光双标技术,观察脱髓鞘的胼胝体区少突胶质细胞变化情况。并通过体质量监测观察小鼠的整体功能状态变化,进一步采用行为学实验技术(旋转棒测试和旷场实验)观察对小鼠运动能力的调控效果和特点。结果与正常组相比,Cuprizone诱导脱髓鞘6周后,脑胼胝体区的髓鞘缺失明显,髓鞘结构蛋白MBP含量明显减少(0.395±0.019)vs(0.242±0.016);P<0.01];应用图像分析和统计学分析发现,成熟少突胶质细胞的胞体(CC-1+)和(MBP+)呈平行性减少(42.62±2.48)vs(25.04±3.68)/100μm2;P<0.05];在实验监测过程中,正常小鼠体质量呈上升增加,而CPZ组小鼠体质量先急剧下降,后趋于平稳并稍有恢复;同时行为学实验结果表明,小鼠的运动协调能力、自发活动能力都有明显减弱(156.17±22.17)vs(78.50±7.80);(240.91±29.52)vs(163.31±21.05);P<0.05],但是对小鼠的探索习性并无明显影响(3.7%/5.4%vs 3.6%/5.3%;P>0.05)。结论利用Cuprizone诱导小鼠脱髓鞘改变与少突胶质细胞减少有关,其主要影响小鼠的运动协调能力和自发活动而不影响探索习性等高级功能。

Effect of cuprizone-induced demyelination on callosal oligodendrocytes and motor function in mice

Objective To study the effect of cuprizone(CPZ)-induced demyelination on callosal oligodendrocytes and motor function in C57BL/6 mice.Methods Six-week old male mice fed with normal diets served as a control group and 6 week old male mice fed with mixed diets containing 0.2% CPZ for 6 weeks served as an experimental group.Demyelination in central nervous system was induced.Demyelination in cerebral callosal region was identified with luxol fast blue(LFB) and myelin structural protein(MBP) immunohistochemical staining.Stability and reliability of the established model were assayed.Demyelinated callosal oligodendrocytes were observed with MBP+CC1 double immunostaining.Overall function of mice was observed by monitoring their body weight.Characteristics of motor function in cerebral callosal region were observed with behavioral tests(Rotarod and open-field test).Results The demyelination in cerebral callosal region was noticeable and the MBP level was significantly lower in experimental group than in control group(0.395±0.019 vs 0.242±0.016,P<0.01) 6 weeks after induction of demyelination.Image and statistical analysis showed that the number of CC-1+ was parallelly decreased with myelin protein of MBP+(42.62±2.48)/100 μm2 vs(25.04±3.68)/100 μm2,P<0.05].The body weight was increased in control group but decreased in experimental group,which then became stable and gradually recovered.Behavioral experiments showed that the motor coordinating function and spontaneous activity were significantly lower in experimental group than in control group(Rotarod test: 156.17±22.17 vs 78.50±7.80;Open-field test: 240.91±29.52 vs 163.31±21.05;P<0.05).However,no significant difference was found in exploration behavior of mice(3.7%/5.4% vs 3.6%/5.3%,P>0.05).Conclusion CPZ-induced demyelination is related with the loss of oligodendrocytes in mice and mainly influences their motor coordinating function and spontaneous activity but not their senior function of exploration behavior.