摘要目的 建立2型糖尿病合并脑缺血树鼩模型,探讨在代谢异常及脑缺血条件下,缺血后适应(postconditioning,PC)对树鼩脑皮层基因表达的调控机制.方法 将70只健康成年树鼩分为对照组、2型糖尿病(T2DM)组、脑缺血(IS)组、T2DM+IS及T2DM+IS+PC组(每组14只).采用高脂饲料饲养联合链脲佐菌素注射建立实验性糖尿病模型,通过光化学反应诱导树鼩局部血栓形成,缺血PC组于缺血后4h夹闭患侧颈总动脉3次(5 min/次)实施PC处理.在脑缺血后24 h,通过血清生化指标的检测了解机体代谢状态,采用TTC、HE染色及电镜超微结构观察对缺血性脑损伤进行评价,用RNA-Seq分析差异表达基因.结果 T2DM+IS组树鼩脑细胞的超微结构明显异常,脑梗死面积达(19.56±1.25)％(P＜0.01).与对照组比较,T2DM+IS组树鼩体重明显下降(P＜0.01),血糖、总胆固醇、低密度脂蛋白胆固醇、三酰甘油和C反应蛋白明显升高(均P＜0.01).RNA-Seq分析结果显示,T2DM+IS组与对照组相比差异表达基因有1 629个(上调基因1 109个,下调基因520个).经缺血PC处理后,皮层梗死面积明显缩小(P＜0.01),血糖、血脂和CRP水平降低(P＜0.05),差异表达基因520个(上调基因203个,下调基因317个).结论 缺血PC可改善2型糖尿病树鼩代谢异常所加剧的缺血性脑损伤,其机制可能与调控大脑皮质基因表达有关.

abstractsObjective To establish tree shrew model of type 2 diabetes mellitus (T2DM) combined with cerebral ischemia (IS),and to explore the regulatory mechanism of ischemic postconditioning (PC) on gene differential expression in cerebral cortex under metabolic abnormalities and cerebral ischemia condition.Methods Seventy tree shrews were divided into control,T2DM,IS,T2DM+IS and T2DM +IS +PC groups (n =14 each group).The experimental diabetes model was established by the combined use of high fat diet breeding with streptozocin injection in tree shrew.The local cerebral thrombosis was induced by photochemical reaction in tree shrews,and ischemic PC was established at 4h after cerebral ischemia followed by clipped ipsilateral common carotid artery three times (5 min/time).The metabolic status of tree shrews was measured by serum biochemical markers.TTC staining,HE staining,and electron microscopy were used to observe the changes of the body's metabolic status at 24h after IS.RNA-seq was used to analyze differentially expressed genes.Results The ultrastructure of brain cells was abnormal and the cerebral infarction area was the largest in T2DM+IS tree shrews (P＜0.01).Compared with control group,body weight of tree shrews in T2DM + IS group was significantly reduced (P＜ 0.01) while blood glucose,total cholesterol,low density lipoprotein-cholesterol,triglyceride,and C-reactive protein (CRP) levels were markedly increased(all P＜0.01).The RNA-seq analysis showed that there were 1 629 differentially expressed genes (1 109 up-regulated genes and 520 down-regulated genes) in T2DM + IS group vs control group.However,ischemic PC deceased the cortical infarction area (P＜0.01)and reduced blood glucose,lipid and CRP levels (P＜0.05),with 520 differential expression genes (203 up-regulated genes and 317 down-regulated genes).Conclusion Ischemic PC improves the metabolic disturbance-aggravated ischemic brain injury in T2DM tree shrews,which may be related to its regulation on gene expression in cerebral cortex.