喹硫平对慢性酒精暴露C57BL/6小鼠胼胝体髓鞘形态和髓鞘碱性蛋白表达的影响

The effects of quetiapine on myelin morphology and expression of myelin basic protein in the corpus callosum of C57BL/6 mice with chronic alcohol exposure

目的 探讨喹硫平对慢性酒精暴露C57BL/6小鼠行为以及胼胝体髓鞘形态、髓鞘碱性蛋白（myelin basic protein,MBP）表达的影响.方法 120只雄性C57BL/6小鼠,采用随机数字表法分为6组（对照组、喹硫平组、酒精模型组、喹硫平低剂量干预组、喹硫平中剂量干预组、喹硫平高剂量干预组）,每组20只.酒精模型组及喹硫平干预组自由饮用体积分数为10％的酒精水溶液20周,喹硫平干预组在饮用酒精水溶液6周后分别加入5、10、15 mg＆#183;kg-1＆#183;d-1的喹硫平干预至20周,喹硫平组饮用纯净水6周后改为10 mg＆#183;kg-1＆#183;d-1的喹硫平水溶液至20周,对照组饮用纯净水20周.造模结束后,采用Morris水迷宫测试各组小鼠学习记忆变化;采用劳克坚牢蓝（luxol fast blue,LFB）染色和电子显微镜观察胼胝体髓鞘形态以及超微结构的改变;免疫荧光法检测小鼠胼胝体MBP表达变化.结果 （1）各组小鼠学习记忆测试结果组间差异有统计学意义（F=4.702,P=0.002）,酒精模型组潜伏期[（22.8±5.5）s]大于对照组[（11.5±7.1） s;t=3.546,P＜0.05];喹硫平低、中剂量干预组[（19.1±8.8）s、（20.1±8.3）s]与酒精模型组比较差异均无统计学意义（t=0.989、0.748,均P＞0.05）;喹硫平高剂量干预组潜伏期[（11.5±5.8）s]小于酒精模型组（t=3.998,P＜0.05）;喹硫平组潜伏期[（10.6±5.5）s]与对照组相比差异无统计学意义（t=0.276,P＞0.05）.（2）LFB染色及电镜结果显示酒精模型组、喹硫平低剂量干预组与对照组相比胼胝体髓鞘有明显的损伤;喹硫平中、高剂量干预组与酒精模型组相比髓鞘完整性有明显的改善;喹硫平组与对照组相比差异无统计学意义.（3）免疫荧光结果显示各组小鼠胼胝体MBP表达组间差异有统计学意义（F=28.971,P＜0.01）,酒精模型组MBP表达（0.038±0.005）明显低于对照组（0.062±0.005;t=8.628,P＜0.05）;喹硫平低剂量干预组（0.043±0.003）与酒精模型组相比差异无统计学意义（t=2.081,P＞0.05）,喹硫平中、高剂量干预组（0.047±0.04、0.058±0.006）均高于酒精模型组（t=3.301、6.645,均P＜0.05）;喹硫平组（0.061±0.005）、喹硫平高剂量干预组与对照组相比差异均无统计学意义（t=0.041、1.137,均P＞0.05）.结论 慢性酒精暴露造成小鼠胼胝体白质髓鞘损伤,学习记忆能力下降;喹硫平中、高剂量干预可能会减轻或者防止慢性酒精使用引起的脑白质髓鞘损伤.

Objective To observe the effects of quetiapine on cognitive function,myelin morphology and expression of myelin basic protein in the corpus callosum of C57BL/6 mice with chronic alcohol exposure.Methods According to random number table,120 male C57BL/6 mice were divided into 6 groups,i.e.,control group,quetiapine control group （10 mg＆#183; kg-1＆#183; d-1quetiapine）,alcohol group,5 mg＆#183; kg-1＆#183; d1quetiapine plus alcohol group,10 mg＆#183; kg-1＆#183; d-1 quetiapine plus alcohol group and 15 mg＆#183;kg-1＆#183; d-1quetiapine plus alcohol group,with 20 mice in each group.Mice in control group and quetiapine control group were maintained with water and solid diet for 20 weeks.Mice in alcohol group and quetiapine plus alcohol groups were maintained with water containing volume fraction of 10% alcohol and solid diet for 20 weeks.Drug with different doses was dissolved in mice drinking for intervention beginning at the 6th week and continuing to the end of the experiment.Morris water maze experiment was used to test the cognitive function.Luxol fast blue （LFB） staining and electron microscopy were used to observe morphology of corpus callosum.The expression of myelin basic protein in the corpus callosum was evaluated with immunofluorescence.Results （1）Morris water maze test showed that the cognition of mice in each group was different （F=4.702,P=0.002）.The latency of mice in alcohol group （（22.8 ±5.5） s） was significantly longer compared with that of the control group（（1 1.5± 7.1） s,t=3.546,P〈0.05）.The latency of 5 mg＆#183; kg1 ＆#183; d-1and 10 mg＆#183; kg-1 ＆#183; d-1quetiapine plus alcohol groups （（19.1±8.8） s,（20.1±8.3） s） were not significantly different compared with that of the alcohol group （t=0.989,0.748,both P〉0.05）.The latency of 15 mg＆#183; kg-1＆#183; d-1quetiapine plus alcohol group（（11.5 ± 5.8） s） was significantly shorter compared with that of the alcohol group （t=3.998,P〈0.05）.The latency of quetiapine control group （（10.6±5.5） s） was not significantly different compared with that of the control group （t=0.276,P〉0.05）.（2）LFB staining and electron microscope results showed severe myelin damage in the corpus callosum of mice in alcohol group,while the integrity of the myelin sheath in 10 mg＆#183; kg-1＆#183; d 1and 15 mg＆#183;kg-1＆#183; d-1quetiapine plus alcohol groups improved significantly compared with the alcohol group.The integrity of the myelin sheath in quetiapine control group was not significantly different compared with that of the control group.（3） Inmunofluorescence results showed that the expression of myelin basic protein of each group was different （F=28.971,P〈0.01）.The expression of myelin basic protein in alcohol group （0.038±0.005） was significantly decreased compared to the control group （0.062±0.005,t=8.628,P〈0.05）.The expression of myelin basic protein in 5 mg＆#183;kg-1＆#183; d-1 quetiapine plus alcohol group （0.043±0.003）was not significantly different compared with the alcohol group （t=2.081,P〉0.05）.The expression of myelin basic protein of 10 mg＆#183;kg-1＆#183; d-1 and 15 mg＆#183;kg-1＆#183; d-1 quetiapine plus alcohol groups （0.047±0.04,0.058±0.006） were significantly increased compared with the alcohol group （t=3.301,6.645,both P〈0.05）.The expression of myelin basic protein in quetiapine control group （0.061±0.005）was not significantly different compared with the control group （t=0.041,1.137,both P〉0.05）.Conclusion Chronic alcohol exposure could induce cognition impairment and white matter myelin danage in mice.Quetiapine treatment may prevent the brain white matter damage due to chronic alcohol exposure in mice.