BK表达在雌二醇介导的大鼠结肠平滑肌收缩中的作用  

Effect of large-conductance calcium-activated potassium channel expression on relaxation of rat colonic smooth muscle regulated by estradiol

作　　者：姜玲[1] 汤玉蓉[1] 熊文婕[1] 俞汀[1] 沈小雪 张灵 林琳[1] JIANG Ling;TANG Yurong;XIONG Wenjie;YU Ting;SHEN Xiaoxue;ZHANG Ling;LIN Lin(Department of Gastroenterology,the First Affiliated Hospital of Nanjing Medical University,Nanjing 210029,China)

机构地区：[1]南京医科大学第一附属医院消化科,江苏南京210029

出　　处：《胃肠病学和肝病学杂志》2018年第11期1233-1238,共6页Chinese Journal of Gastroenterology and Hepatology

摘　　要：目的探讨大电导钙激活钾通道(BK)在17β-雌二醇(E2)介导的大鼠结肠平滑肌收缩中的作用及机制。方法 24只雌性SD大鼠去除双侧卵巢后背部皮下埋植30 mm硅胶管,内含不同溶液。随机分为以下4组:(1)对照组:溶剂玉米油;(2) E2组:含质量浓度为0. 3 g/L的E2,使血清E2保持在生理浓度;(3) EI组:含相同浓度E2及E2抑制剂(ICI 182780);(4)牛血清白蛋白结合E2(BSA-E2)组:含质量浓度为0. 3 g/L的BSA-E2。各组干预14 d后,免疫荧光、Western blotting及qRT-PCR检测结肠平滑肌组织BK分布及表达。免疫荧光双标法检测BK与α肌动蛋白共表达。不同时间及不同浓度E2刺激后,Western blotting及qRT-PCR检测结肠平滑肌细胞(SMCs)中BK表达;检测E2、雌激素受体阻断剂ICI 182780、BSA-E2、雌激素α受体激动剂PPT及β受体激动剂DPN对结肠平滑肌BK表达的影响。结果 E2组结肠平滑肌BK表达高于对照组、EI组及BSA-E2组,差异有统计学意义(P <0. 05)。结肠SMCs上存在BK。50 nmol/L E2刺激24 h可显著促进BK表达。与对照组相比,E2组、雌激素β受体激动剂DPN组均可上调结肠SMCs BK表达(P <0. 05)。EI组、BSA-E2组与对照组比较,差异无统计学意义(P> 0. 05)。结论 E2可上调BK表达,此作用可由β受体介导。Objective To investigate the effect and mechanism of the expression of large-conductance calciumactivated potassium channel（ BK） on relaxation of rat colonic smooth muscle regulated by 17β-estradiol（ E2）.Methods Twenty-four female Sprague-Dawley（ SD） rats were randomly divided into 4 groups,and all groups were under ovariectomy. A 30 mm silicone tube filled with different solutions was subcutaneously implanted in different groups of rats. Control group was filled with the solvent; E2 group was given E2 in corn oil（ 0. 3 g/L） which could keep serum level of E2 at physiological level; EI group was given ICI 182780（ estrogen receptor antagonist） plus E2 and bovine serum albumin-bound（ BSA-E2） group was filled with BSA-E2. After 14 days of intervention,BK distribution and expression in colonic smooth muscle were detected by immunofluorescence,Western blotting and qRT-PCR. Double immunofluorescence staining was used to observe the expressions of BK and α-SMA. The expression of BK in colon smooth muscle cells（ SMCs） was detected by Western blotting and qRT-PCR at different time and concentrations of E2.The effects of E2,ER inhibitor ICI 182780,BSA-E2,ERα selective agonist propyl pyrazole triol（ PPT） and ERβselective agonist diarylpropiolnitrile（ DPN） on BK expression were observed. Results The BK expression of colonic smooth muscle in E2 group was higher than that in control group,EI group and BSA-E2 group（ P〈0. 05）. Double immunofluorescence staining showed that BK and α-actin co-expressed in rat colonic SMCs. Treatment with 50 nmol/L E2 for 24 hours could significantly increase the expression of BK（ P〈0. 05）. The expression of BK in DPN group and E2 group was both higher than that in control group（ P〈0. 05）. There was no significant difference among EI group,BSA-E2 group and control group（ P〉0. 05）. Conclusion E2 can up-regulate the expression of BK,which can be mediated by β receptor.

关 键 词：雌二醇 大电导钙激活钾通道 平滑肌 肌细胞 结肠 

分 类 号：R574.62[医药卫生—消化系统]