TRIM16在2型糖尿病认知功能障碍大鼠脑海马神经元凋亡中的表达变化

摘要

目的 研究链脲佐菌素(streptozotocin,STZ)诱导的2型糖尿病大鼠海马组织中TRIM16 (Tripartite motif-containing 16)的变化与其糖尿病大鼠认知功能障碍及海马组织细胞凋亡的关系.方法 将8周龄雄性SD大鼠随机分成糖尿病组(DM组)(n=25)和正常对照组(NC组)(n=15).NC组正常饲料,DM组大鼠给予高糖高脂饲料喂养,25 mg/kg STZ腹腔注射,尾静脉血糖＞16.7 mmol/L者,视为造模成功,NC组大鼠腹腔注射等量柠檬酸缓冲液;建模成功后将2组大鼠分别喂养17周,Morris水迷宫实验检测2组大鼠认知功能;2组大鼠灌注后取脑,免疫组化检测海马组织TRIM16蛋白表达,TUNEL法检测海马组织细胞凋亡情况;取2组大鼠新鲜海马组织,Western blotting检测TRIM16、Bax和Bcl-2蛋白的表达.结果 成模17周,与NC组比较,DM组大鼠逃避潜伏期延长和原平台所在象限停留时间减少(P＜0.01);DM组大鼠海马CAl区锥体细胞出现明显凋亡,阳性神经元的细胞核呈棕黄色,核固缩深染.DM组大鼠海马组织TRIM16表达增加(P＜0.01),Bcl-2表达无明显变化,Bax的表达及Bax/Bcl-2比值明显增加(P＜0.01). 结论 TRIM16通过促进STZ诱导的2型糖尿病大鼠海马组织凋亡参与糖尿病认知功能障碍,为糖尿病脑病提供新的实验依据和潜在的治疗靶点.%Objective To study the relationship between the changes of TRIM16 in hippocampus of type 2 diabetic rats induced by streptozotocin (STZ) and cognitive dysfunction and apoptosis of hippocampal cells.Methods The male Sprague-Dawley (SD) rats of 8 weeks old were randomly divided into diabetic group (DM group) (n=25) and normal control group (NC group) (n=15).NC group were given normal feed, DM rats were fed with high glucose and high fat diet,followed by low dose of STZ (25 mg/kg, intraperitoneal injection), induced compensatory secretion of insulin, five days after the detection of tail vein blood glucose>16.7 mmol/L, and established the STZ.Meanwhile, citric acid buffer was injected to rats in group as control.After successful modeling, the rats in the two groups were fed with 17 weeks.Morris water maze test was used to detect the cognitive function of the two groups of rats.The protein expression of TRIM16, Bax and Bcl-2 protein in fresh hippocampus tissue of DM group and NC group rats was detected using western blotting.Rats in DM group and NC group were perfused with brain, and the hippocampal tissues were stained with immunohistochemistry.TUNEL method was used to detect the apoptosis of hippocampus cells.Results Compared with NC group, morris water maze test showed that the escape latency of rats in DM group is longer than NC group, staying at the original platform quadrant time in DM group is less than the NC group.TUNEL assay showed that after injection of 17 weeks, hippocampal CA1 pyramidal cells in type 2 diabetic rats appeared obvious apoptosis, positive neurons in the nuclei were brown, karyopyknosis anachromasis, while control group of neurons in the nucleus without brown coloring.Compared with the NC group, hippocampus immunohistochemistry results showed that the protein of TRIM16 in hippocampus CA1 region of type 2 diabetic rats was increased, cytoplasm brown, coarse granular.Compared with the NC group, the expression of Bcl-2 had no obvious change in hippocampus of type 2 diabetic rats at 17 weeks, while the expression of TRIM16, Bax and the ratio of Bax/Bcl-2 was significantly increased (P<0.05).Conclusion The protein expression of TRIM16 using immunohistochemical and Western blotting in hippocampus of diabetic rats induced by STZ was increased.There is apoptosis in hippocampus of diabetic rats induced by STZ, the expression of Bcl-2 was not significantly changed, the expression of Bax and the ratio of Bax/Bcl-2 were significantly increased.TRIM16 is involved in diabetic cognitive dysfunction by promoting apoptosis of diabetic rat hippocampus.