酒精依赖伴高脂大鼠海马TGF-β/Smad表达变化及其对认知功能的影响

Effect of high fat diet and alcohol dependence on cognitive function and expression of TGF-β/Smad in hippocampus of rats

目的探讨高脂饮食、酒精对大鼠认知能力的影响及其与海马TGF-β/Smad通路表达的关系。方法将20只SD大鼠随机分组:对照组(n=4)、酒精组(n=8)、酒精+高脂饮食组(n=8)。在造模28d后,利用Morris水迷宫检测大鼠学习记忆能力,伊红-苏木素染色(HE染色)显示海马神经元结构,酶联免疫吸附(ELISA)实验检测TGF-β1水平,Western-blot检测海马内P-Smad3和Smad4水平。结果(1)在Morris水迷宫定位航行训练的第6天,酒精+高脂饮食组大鼠的潜伏期较对照组显著延长,差异有统计学意义(P<0.05);酒精组、酒精+高脂饮食组大鼠运动轨迹较对照组复杂、混乱,趋向性差;在空间探索试验中,对照组大鼠穿越平台次数为(6.00±0.91)次,酒精组大鼠为(4.25±0.53)次,酒精+高脂饮食组大鼠为(3.60±0.46)次,差异有统计学意义(P<0.05);(2)HE染色显示两个模型组大鼠海马神经元细胞均有不同程度的细胞形态异常;(3)TGF-β1在各组大鼠海马表达水平分别为对照组(2293.38±132.36)pg/ml、酒精组(2444.81±99.99)pg/ml、酒精+高脂饮食组(2690.02±81.16)pg/ml,对照组与酒精+高脂饮食组相比差异具有统计学意义(P<0.05);(4)P-Smad3、Smad4水平在对照组、酒精组、酒精+高脂饮食组大鼠的表达逐渐增加;与对照组相比,酒精组、酒精+高脂饮食组P-Smad3、Smad4表达显著增加,差异均具有统计学意义(P<0.05)。结论高脂饮食和酒精可能通过增强海马TGF-β1、P-Smad3、Smad4的表达而影响其功能,导致大鼠空间学习记忆能力下降。

Objective To explore the effect of high fat diet and alcohol on cognitive ability in rats,and the relationship between the effect and TGF-β/Smad expression in hippocampus.Methods Twenty SD rats were randomly divided into control group(n=4),alcohol group(n=8)and alcohol+high fat diet group(n=8).After 28 days of model establishment,the learning and memory ability of rats was detected by Morris water maze,the structure of hippocampal neurons was visualized by eosin-hematoxylin staining(HE staining),the level of TGF-β1 was detected by enzyme-linked immunosorbent assay(ELISA),and the levels of P-Smad3 and Smad4 in the hippocampus were detected by Western-blot.Results(1)On the 6th day of Morris water maze localization navigation training,the latency of rats in alcohol+high fat diet group was significantly longer than that in control group,and the difference was statistically significant(P<0.05).The movement trajectory of rats in alcohol group and alcohol+high fat diet group was more complex and confusing than that in control group,and the tropism was poor.In spatial exploration test,the number of platform crossings of rats in control group,alcohol group and alcohol+high fat diet group was(6.00±0.91),(4.25±0.53)and(3.60±0.46)times respectirely,the difference was significant(P<0.05).(2)HE staining showed that the hippocampal neuronal cells of rats in the two model groups had different degrees of abnormal cell morphology.(3)The expression level of TGF-β1 in the hippocampus of rats in each group were(2293.38±132.36)pg/ml in control group,(2444.81±99.99)pg/ml in alcohol group,and(2690.02±81.16)pg/ml in alcohol+high fat diet group respectively,and the difference was statistically significant between control group and alcohol+high fat diet group(P<0.05).(4)The expression of P-Smad3 and Smad4 were gradually increased in control group,alcohol group and alcohol+high fat diet group.The expression of P-Smad3 and Smad4 were significantly increased in alcohol group and alcohol+high fat diet group compared with control group,the differences were statistically significant(P<0.05).Conclusion High fat diet and alcohol may affect the function of rats by enhancing the expression of TGF-β1,P-Smad3 and Smad4 in hippocampus,which leads to the decrease of spatial learning and memory ability in rats.