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目的:探讨长期高脂饮食引起的胰岛素抵抗对pR5株系MAPT Tau转基因小鼠的认知功能和大脑Tau蛋白磷酸化的影响。方法:8周龄雌性pR5 MAPT转基因小鼠分为标准饮食(standard diet，STD)组(pR5 STD，n n＝8)和高脂饮食(high-fat diet，HFD)组(pR5 HFD，n n＝8)，以STD喂养的雌性野生型(wild type，WT)C57BL/6小鼠为对照组(WT STD，n n＝8)，连续干预30周，直到小鼠老龄。实验期间小鼠每周测量1次体质量，每2周测量1次空腹血糖。30周后进行葡萄糖耐量实验、胰岛素耐量实验；采用强迫游泳实验和悬尾实验评估小鼠抑郁样行为，高架十字迷宫实验评估焦虑样行为，Morris水迷宫空间探索实验评估记忆行为；Western blot检测大脑组织总Tau蛋白和磷酸化Tau蛋白H7-tau、p-tau-Ser396和p-tau-Thr231表达水平。采用SPSS 17.0进行统计分析，葡萄糖耐量数据和胰岛素耐量数据采用重复测量方差分析，其他数据多组间比较采用单因素方差分析，进一步两两比较采用LSD检验。n 结果:高脂饮食30周时，三组小鼠的体质量和空腹血糖均差异有统计学意义(n F＝808.31，1 117.18，均n P<0.01)。pR5 HFD组小鼠的体质量[(54.35±2.52)g]高于pR5 STD组[(24.95±1.15)g]和WT STD组[(23.86±1.10)g](均n P<0.01)，pR5 HFD组小鼠空腹血糖[(8.12±0.24)mmol/L]高于pR5 STD组[(4.64±0.13)mmol/L]和WT STD组[(4.45±0.22)mmol/L] (均n P<0.01)。葡萄糖耐量实验显示，三组小鼠注射葡萄糖后的120 min内，血糖值存在显著时间和组别交互作用(n F＝113.30，n P<0.01)，pR5 HFD组小鼠注射葡萄糖后血糖升高的峰值延迟，提示pR5 HFD组小鼠葡萄糖耐量受损。胰岛素耐量实验显示，三组小鼠的胰岛素耐量存在显著的时间和组别的交互作用(n F＝209.92，n P<0.01)。pR5 HFD组小鼠注射胰岛素后，血糖下降较慢，在60 min时即达谷值，之后血糖显著回升，提示pR5 HFD组小鼠对胰岛素的敏感性显著降低。三组小鼠强迫游泳不动时间百分比和悬尾不动时间百分比均差异有统计学意义(n F＝37.05，59.29，均n P<0.01)，pR5 STD组和pR5 HFD组的这两个指标均高于WT STD组(均n P<0.01)，且pR5 HFD组高于pR5 STD组(n P<0.01)。高架十字迷宫结果显示，三组小鼠在开放臂中的活动距离和活动时间均差异有统计学意义(n F＝7.82，10.37，均n P<0.05)。pR5 HFD组小鼠的活动距离[(0.40±0.21)m]和活动时间[(27.38±8.80)s]均低于pR5 STD组[(2.31±1.74)m，(63.56±27.52)s](均n P<0.05)。空间探索实验显示，pR5 HFD组小鼠目标象限停留时间[(15.56±1.16)s]少于pR5 STD组[(19.18±0.64)s](n P<0.01)，pR5 HFD组小鼠进入平台区域时间[(1.43±0.06)s]少于pR5 STD组[(1.66±0.12)s](n P<0.01)。Western blot结果显示，三组小鼠总Tau蛋白、H7-tau、p-tau-Ser396和p-tau-Thr231蛋白表达水平均差异有统计学意义(n F＝101.50，80.60，55.47，30.89，均n P<0.05)。两两比较显示，pR5 STD组、pR5 HFD组四种Tau蛋白表达均高于WT STD组(均n P<0.01)，pR5 HFD组均高于pR5 STD组(均n P<0.05)。n 结论:长期高脂饮食引起肥胖、高血糖和外周胰岛素抵抗，促进了MAPT小鼠的认知损害，与MAPT小鼠大脑中Tau蛋白磷酸化增加有关。“,”Objective:To investigate the effects of insulin resistance induced by long-term high-fat diet on cognitive function and brain phosphorylated Tau protein in pR5 MAPT Tau transgenic mice.Methods:Eight-week-old female pR5 MAPT transgenic mice were divided into standard diet(STD) group (pR5 STD, n n=8) and high-fat diet(HFD) group (pR5 HFD, n n=8). Female wild-type C57BL/6 mice fed with STD were used as control group (WT STD, n n=8). The experiment was carried out for 30 weeks until the mice were old.During the experiment, the weight of mice was measured once a week and fasting blood glucose was measured once every two weeks.Thirty weeks later, glucose tolerance test and insulin tolerance test were carried out.Forced swimming test and tail suspension test were used to evaluate the depressive behavior of mice, and elevated plus maze test was used to evaluate the anxiety behavior, Morris water maze test was used to evaluate spatial memory behavior.The levels of total Tau protein and phosphorylated Tau proteins H7-tau, p-tau-Ser396 and p-tau-Thr231 were detected by Western blot.SPSS 17.0 software was used for statistical analysis, repeated measurement ANOVA was used for the data of glucose tolerance test and insulin tolerance test, one-way ANOVA was used for multi group comparison, and LSD test was used for further pairwise comparison.n Results:After 30 weeks of high-fat diet, there were significant differences in body weight and fasting blood glucose among the three groups (n F=808.31, 1 117.18, both n P<0.01). The body weight of mice in pR5 HFD group ((54.35±2.52)g) was higher than those in pR5 STD group ((24.95±1.15) g) and WT STD group ((23.86±1.10) g) (bothn P<0.01), and the fasting blood glucose of mice in pR5 HFD group ((8.12±0.24) mmol/L) was significantly higher than those in pR5 STD group ((4.64±0.13) mmol/L) and WT STD group ((4.45±0.22) mmol/L) (bothn P<0.01). Glucose tolerance test showed that within 120 minutes after injection of glucose, there was a significant time and group interaction in the blood glucose value among the three groups (n F=113.30, n P<0.01). After glucose injection, the peak value of blood glucose in pR5 HFD group was delayed, suggesting that glucose tolerance in pR5 HFD group was impaired.The insulin tolerance test showed that there was a significant interaction between time and group in the insulin tolerance among the three groups (n F=209.92, n P<0.01). After injection of insulin, the blood glucose in pR5 HFD group decreased slowly, reaching the valley value at 60 min, and then the blood glucose increased significantly, suggesting that the sensitivity of pR5 HFD group mice to insulin decreased significantly.There were significant differences in the percentage of forced swimming immobility time and tail suspension immobility time among the three groups (n F=37.05, 59.29, both n P<0.01). The two indexes of pR5 STD group and pR5 HFD group were both higher than those of WT STD group (alln P<0.01), and those of pR5 HFD group were both higher than those of pR5 STD group (bothn P<0.01). The results of elevated plus maze showed that there were significant differences in the activity distance and time in open arm among the three groups (n F=7.82, 10.37, both n P<0.05) .The activity distance ((0.40±0.21) m) and activity time ((27.38±8.80) s) of pR5 HFD group were significantly lower than those of pR5 STD group ((2.31±1.74) m, (63.56±27.52)s) (bothn P<0.05). The space exploration test showed that the residence time in the target quadrant of pR5 HFD group ((15.56±1.16)s) was less than that of pR5 STD group((19.18±0.64)s)(n P<0.01), and the time of entering the platform area of pR5 HFD group((1.43±0.06)s) was less than that of pR5 STD group((1.66±0.12)s)(n P<0.01). Western blot showed that there were significant differences in the levels of total Tau protein, H7-tau, p-tau-Ser396 and p-tau-Thr231 protein among the three groups (n F=101.50, 80.60, 55.47, 30.89, all n P<0.05). Further pairwise comparison showed that the levels of the four Tau proteins showed: the levels of the proteins in pR5 STD group and pR5 HFD group were all higher than those of WT STD group (alln P<0.01), and those in pR5 HFD group were all higher than those in pR5 STD group (alln P<0.05).n Conclusion:Long-term high fat diet causes obesity, hyperglycemia and peripheral insulin resistance, and promotes the cognitive impairment of MAPT mice, which is related to the increase of Tau protein phosphorylation in the brains of MAPT mice.