右旋美托咪啶通过Akt/Bad通路抑制异氟醚引起的新生大鼠海马细胞凋亡  

Dexmedetomidine attenuates isoflurane-induced hippocampal neuroapoptosis through activation of Akt /Bad signaling pathways in neonatal rats

作　　者：韩雪[1] 胡楚文[1] 李玉娟[1] 廖朝霞[1] 柳垂亮 

机构地区：[1]中山大学孙逸仙纪念医院麻醉科,广东广州5101202 [2]广东省佛山禅城中心医院麻醉科,广东佛山528030

出　　处：《中国药理学通报》2013年第12期1702-1706,共5页Chinese Pharmacological Bulletin

基　　金：国家自然科学基金资助项目(No 30700787;C03030301);广东省自然科学基金资助项目(No S2011010004558)

摘　　要：目的研究右旋美托咪啶(dexmedetomidine,Dex)对异氟醚所致新生大鼠海马细胞凋亡的保护作用及与Akt/Bad信号通路的关系。方法出生7 d SD大鼠随机分为空气组(Air+NS)、二甲基亚砜组(Air+DMSO)、LY294002组(Air+LY)、异氟醚组(Iso+NS)、异氟醚+Dex组(Iso+Dex)、异氟醚+Dex+LY294002组(Iso+Dex+LY)。前3组吸入空气6h,后3组吸入体积分数为0.0075异氟醚6h。吸入异氟醚前40min,Air+DMSO组、Air+LY组和Iso+Dex+LY组分别经侧脑室注射5μl体积分数为0.1的DMSO或25μg LY294002;Iso+Dex组和Iso+Dex+LY组分别在麻醉0、2、4 h腹腔内注射Dex 25μg·kg-1;Air+NS组和Iso+NS组在同时间点腹腔内注射等体积生理盐水。Western blot法检测海马激活型caspase-3、Akt、磷酸化Akt(p-Akt)、Bad、磷酸化Bad(p-Bad)、Bcl-xl蛋白表达变化(n=5),TUNEL法检测海马CA1区细胞凋亡(n=5)。结果 Dex可明显减少异氟醚引起的海马CA1区TUNEL阳性细胞表达(P<0.01),减低激活型caspase-3(P<0.01)和Bad蛋白表达(P<0.01),上调p-Akt/Akt、p-Bad/Bad和Bcl-xl/Bad比值(P<0.01)。LY294002逆转了Dex对上述蛋白表达的影响。结论Dex通过激活Akt/Bad信号通路减少异氟醚诱导的新生大鼠海马细胞凋亡。Aim To investigate the protective effect of dexmedetomidine on isoflurane-induced hippocampal neuroapoptosis and the relationship with Akt/Bad sig- naling pathway in neonatal rats. Methods SD rat pups at postnatal day 7 were randomly assigned to Air ＋ NS group, Air ＋ DMSO group, Air ＋ LY group, Iso ＋NS group, Iso ＋ Dex group, and Iso ＋ Dex ＋ LY group. Rats were exposed to air or isoflurane （volume fraction of 0. 0075） for 6h. Rats in the groups of Air ＋ LY, Iso ＋ Dex ＋ LY or Air ＋ DMSO were injected in- traventricularly with LY294002 25 μg or DMSO （ volume fraction of 0. 1 ） 5μl separately 40 minutes before isoflurane exposure. Rats in the groups of Iso ＋ Dex and Iso ＋ Dex ＋ LY were injected intraperitoneally with 25μg · kg^-1 dexmedetomidine for three times （at Oh, 2 h and 4 h during isoflurane exposure） , while rats in the groups of Air ＋ NS and Iso ＋ NS were injected in- traperitoneally with isovolumetric saline instead. Pro- tein levels of cleaved easpase-3, Akt, phospho-Akt（p-Akt）, Bad, phospho-Bad （p-Bad） and Bcl-xl were detected by Western blot （n =5）. Cytoapoptosis in CA1 area was tested by Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling （TUNEL） staining （ n = 5 ）. Results Dexmedetomidine signifi- cantly decreased TUNEL positive cells in CA1 area （P 〈0.01） and the cleaved caspase-3 （ P 〈 0.01 ） and Bad （P 〈 0. 01） levels induced by isoflurane, in- creased the ratios of p-Akt/Akt, p-Bad/Bad and Bcl- xl/Bad （P 〈0.01, P 〈0.01, P 〈0.01）. These dexmedetomidine-induced changes could be reversed by pretreatment with LY294002. Conclusions Dexmedetomidine attenuates isoflurane-induced hipp- ocampal neuroapoptosis through activation of Akt/Bad signaling pathways in neonatal rats.

关 键 词：异氟醚 右旋美托咪啶 海马 凋亡 原癌基因蛋白c-Akt Bcl相关死亡蛋白 

分 类 号：R-332[医药卫生] R322.81