高脂饮食和酒精依赖对大鼠记忆及前额叶TGF-β/Smad通路的影响

Effects of high fat diet and alcohol dependence on memory and expression of TGF-β/Smad pathway in prefrontal cortex of rats

目的研究高脂饮食和酒精依赖对大鼠学习记忆能力及前额叶皮质(Prefrontal cortex,PFC)锥体细胞TGF-β/Smad通路的影响。方法将24只雄性SD大鼠随机分为对照组(n=8)、酒精组(n=8)、酒精+高脂饮食组(n=8)。给予对照组大鼠自由饮用灭菌水,其余两组单瓶自由饮用酒精(3%~12%),高脂饲料仅向酒精+高脂饮食组提供。造模28 d后利用Morris水迷宫检测大鼠空间学习记忆能力,伊红-苏木素染色(HE染色)显示PFC结构,ELISA及蛋白质免疫印迹(Western blotting)检测PFC中TGF-β1、P-Smad3和Smad4的表达。结果Morris水迷宫定位航行训练第6天,与对照组潜伏期相比,酒精组大鼠平均潜伏期(27.15±7.20)S、酒精+高脂饮食组大鼠平均潜伏期(28.90±3.70)S差异具有统计学意义(P均<0.05);空间探索实验中,与对照组大鼠穿越平台次数(6.00±0.91)次相比,酒精组大鼠(4.25±0.53)次(P>0.05),酒精+高脂组大鼠(3.60±0.46)次(P<0.05);酒精组、酒精+高脂组大鼠PFC镜下神经元细胞对比对照组明显损伤;ELISA结果显示对照组、酒精组、酒精+高脂组大鼠前额叶TGF-β1表达分别为(1578.75±136.25)pg/mL、(3031.81±431.17)pg/mL、(3824.17±113.04)pg/mL,与对照组相比,两个模型组PFC的TGF-β1表达明显增加(P均<0.05);Western blotting结果显示对照组、酒精组、酒精+高脂组大鼠前额叶P-Smad3、Smad4表达呈逐渐上升趋势,与对照组相比,酒精+高脂组P-Smad3和Smad4的表达均具有统计学意义(P均<0.05)。结论高脂饮食和酒精依赖可能通过增强前额叶TGF-β/Smad通路表达而影响其功能,导致大鼠空间学习记忆能力下降。

Objective To investigate the effects of high-fat diet and alcohol dependence on learning and memory ability and TGF-β/Smad expression in pyramidal cells of prefrontal cortex(PFC)in rats.Methods Twenty-four male SD rats were randomly divided into control group(n=8),alcohol group(n=8)and alcohol+high-fat diet group(n=8).The rats in the control group were given free access to sterilized water,the other two model groups were given a single bottle of alcohol(3%~12%),and the high-fat diet was only provided to the alcohol+high-fat diet group.After 28 days of modeling,Morris water maze was used to detect the spatial learning and memory ability of rats,eosin hematoxylin staining(HE staining)was used to show the PFC structure,and ELISA and Western blotting were used to detect the expression of TGF-β1,P-Smad3 and Smad4 in the frontal lobe.Results The results on the 6th day of Morris water maze positioning navigation training,compared with the latency of the control group,the average latency of rats in the alcohol group was(27.15±7.20)s,and the average latency of rats in the alcohol+high-fat diet group was(28.90±3.70)s(P<0.05).In the space exploration experiment,compared with the number of crossing the platform of rats in the control group(6.00±0.91)times,the average latency of rats in the alcohol group was(4.25±0.53)times(P>0.05),rats in alcohol+high-fat diet group(3.60±0.46)times(P<0.05).The neurons of PFC in alcohol group and alcohol+high-fat diet group were significantly damaged compared with the control group.ELISA results showed that TGF-β1 expression was(1578.75±136.25)pg/mL,(3031.81±431.17)pg/mL and(3824.17±113.04)pg/mL in the prefrontal cortex of rats in the control group,alcohol group and alcohol+high fat group,respectively.TGF-β1 expression of PFC increased significantly in both model groups(P<0.05 for all).Western blotting results showed that the expressions of P-Smad3 and Smad4 in the prefrontal lobe of rats in the control group,alcohol group and alcohol+high fat group were gradually increased.Compared with the control group,the expressions of P-Smad3 and Smad4 in the alcohol+high fat group were statistically significant(P<0.05 for all).Conclusion High-fat diet and alcohol dependence may affect the function of prefrontal cortex by enhancing the expression of TGF-β1,P-Smad3 and Smad4,resulting in the decrease of spatial learning and memory ability in rats.