【摘要】 目的:探究有氧运动对高血压大鼠(SHR)肠系膜动脉血管平滑肌细胞大电导钙激活钾(BKCa)通道α和β1亚基蛋白表达及血管舒缩性的影响。方法:选用12周龄雄性自发性高血压大鼠(SHR,n=24)以及正常血压对照组(WKY,n=12)。将SHR随机分组,高血压安静对照组(SHR,n=12)和高血压有氧运动组(SHR-EX,n=12),各组大鼠先进行1周适应性训练,之后SHR-EX组进行为期8周的跑台训练。9周后,取各组大鼠的肠系膜动脉(2~3级),进行HE染色,离体微血管张力测定及蛋白免疫印迹分析。结果:(1)SHR组肠系膜动脉的管壁厚度明显高于WKY组(P<0.01),但SHR-EX组肠系膜动脉的管壁厚度明显低于SHR组(P<0.01);(2)Iberiotoxin(10-7M)作为BKCa通道选择性阻断剂可诱发各组血管张力增加,增高幅度为SHR>SHR-EX>WKY,NS11021作为BKCa通道选择性激动剂可使血管张力下降,下降幅度为SHR>SHE-EX>WKY;(3)SHR组BKCa通道的α和β1亚基表达上调,且以β1亚基上调更为显著,SHR-EX组的两亚基上调减弱,且以β1亚基变化更为显著。结论:高血压诱导大鼠肠系膜动脉BKCa通道功能增强,负反馈调节血管张力增加,但有氧运动可显著抑制高血压伴随的大鼠肠系膜动脉BKCa通道的α和β1亚基表达上调,从而改善血管功能。更多还原

【Abstract】 Objective:The present study was designed to investigate the effects of chronic exercise on the molecular expression of α- and β1-subunit oflarge-conductance Ca2+-activated K+(BKCa)channels and vascular contractility in rat mesenteric arterial smooth muscle cells from spontaneously hyperten-sive rats. Methods:Three-month-old male normotensive Wistar-Kyoto rats(WKY,n=12)and SHRs(n=24)were used. SHRs(n=24)were separated into asedentary group(SHR)and an exercise group(SHR-EX)at random(n=12 in each group). After a 1-week acclimation period,rats in SHR-EX were sub-jected to aerobic exercise on a motor-driven treadmill. After 8 weeks,HE staining was used to analyze the vascular morphology change. Mesenteric arterialtensions were measured in vitro. Immunohistochemistry and Western blots assay were also conducted. Results:1)Compared with WKY,the systolic bloodpressure and pulse pressure were significantly increased with hypertension(P <0.01). However,they significantly dropped in SHR-EX compared with its sed-entary group(P<0.01). 2)The wall thickness of mesenteric artery in hypertension group was obviously increased,but it effectively decreased in SHR-EXcompared with SHR. Selective BKCa channel blocker(Iberiotoxin10-7M)induced a marked increase of vascular tension in MAs in all three groups. Howev-er,these effects were greatly increased in SHR group. 3)Selective BKCa channel activator(NS11021)induced concentration-dependent vasorelaxation inMAs precontracted with norepinephrine. However,these effects were greatly decreased in SHR group. 4)Western blotting showed that the protein expressionof BKCa α- and β1-subunit was significantly increased with hypertension,and the increase of β1 subunits was larger than that of α subunits,whereas aero-bic exercise could effectively ameliorate the changes. Conclusions:Hypertension is associated with an increase of BKCa channel protein expression,which isa negative feedback to regulate vascular contractility,whereas aerobic exercise can significantly weaken this hypertension-associated pathological up-regula-tion of BKCa channels to improve the vascular function.更多还原