高脂饮食对大鼠脑微血管内皮细胞HIF-1α及Claudin-5表达的影响

目的研究高脂饮食对大鼠脑微血管内皮细胞HIF-1α及Claudin-5表达的影响,初步探讨高脂毒性对大鼠脑微血管的损伤机制。方法 (1)40只SD大鼠随机分为高脂组与正常对照组,每组20只,分别予以高脂饲料和普通饲料喂养8周。(2)测定各组大鼠基础、第4周、第8周时体重及代谢指标变化。(3)8周时处死各组大鼠,免疫组化检测各组大鼠脑微血管内皮细胞上HIF-1α及Claudin-5蛋白表达情况,伊文氏蓝(EB)染色检测血-脑屏障(BBB)的通透性。结果 (1)高脂组大鼠体重由基础值(165.00±12.100)g增加至8周时的(401.30±66.827)g;对照组大鼠体重由基础值(163.00±10.100)g增加至8周时的(321.10±18.300)g,两组比较差异有统计学意义(P<0.05)。(2)高脂组大鼠空腹血总胆固醇(TC)由基础值(1.576±0.138 9)mmol/L升高为8周时的(2.032±0.365 0)mmol/L,甘油三酯(TG)由基础值(0.601±0.117 2)mmol/L升高至8周时的(2.679±1.087 6)mmol/L,且显著高于相应时间点正常对照组(P<0.05)。(3)8周时高脂组大鼠脑皮质微血管内皮细胞上,HIF-1α表达强于正常对照组(P<0.05),Claudin-5表达呈弱阳性,正常对照组大鼠Claudin-5呈强阳性表达(P<0.05)。(4)8周时高脂组大鼠EB含量较正常对照组升高,差异有统计学意义(P<0.05)。结论高脂可通过上调HIF-1α蛋白的表达水平使紧密连接蛋白Claudin-5的表达下降,导致微血管病变及增加BBB的通透性。

Effect of high fat diet on claudin-5 expression in rat brain microvascular endothelial cells

Objective To investigate the effect of high-fat diet on HIF-1αand Claudin-5 expression in rat brain microvascular endothelial cells, preliminary study injury mechanism of fat toxicity on rat brain microvascular. Methods （1）40 SD rats were randomly divided into high-fat group （n=20） and normal food groups （n=20）, respectively to be fed with high fat diet and regular food eight weeks. （2）The weight, TG and TC of rats in each group were detected in baseline, 4 weeks and 8 weeks . （3）The rats were killed after 8 weeks, the protein level of HIF-1α, and Claudin-5 in the brain microvascular endothelial cells were determined by immunohistochemistry staining. Evans blue staining detect blood-brain barrier permeability. Results （1）High-fat groups＇ weight increased from （165.00±12.100）g to （401.30±66.827）g, control groups＇ weight increased from （163.00±10.100）g to （321.10±18.300）g, the difference was statistically significant （P〈0.05） on 8 weeks; （2）High-fat groups＇ fasting TC by the underlying value of （1.576±0.138 9）mmol/L increased to 8 weeks of （2.032±0.365 0）mmol/L, TG by the underlying value of （0.601±0.117 2）mmol/L increased to （2.679±1.087 6）mmol/L at 8 weeks, and significantly higher than the corresponding time points normal control group （P〈0.05）. （3）High-fat group rat brain cortex microvascular endothelial cells, HIF-1α expression was stronger than the normal control group after 8 weeks （P〈0.05）, Claudin-5expression was weakly positive, normal control rats Claudin-5 expression was strongly positive （P〈0.05）. （4）EB content of high-fat group increased compared with normal control group, the difference was statistically significant （P〈0.05） after 8 weeks. Conclusion Hyperlipidemia can increase HIF-1αprotein levels and lead to tight junction protein Claudin-5 expression decreased, resulting in microvascular disease and increasing BBB permeability.