右美托咪定对肺癌小鼠低氧时HIF-1α信号通路的影响

Effect of dexmedetomidine on hypoxia-inducible factor-1alpha signaling pathway during hypoxia in mice with lung cancer

目的评价右美托咪定对肺癌小鼠低氧时低氧诱导因子(HIF)-1α信号通路的影响。方法清洁级健康雄性BALB/c裸鼠18只,8周龄,体重20~30 g。采用随机数字表法分为3组(n=6):肺癌组(L组)、低氧+肺癌组(HL组)和低氧+肺癌+右美托咪定组(HLD组)。经尾静脉注射人肺腺癌A549细胞悬液1×10^6/150μl,制备小鼠肺癌模型。模型制备成功后,行慢性间歇性低氧处理:小鼠放入密闭容器中,进气孔通入10%O2,持续3 h,1次/d,持续3周。HL组予低氧处理;HLD组低氧处理结束后,腹腔注射右美托咪定25μg/kg,3次/周,共3周。L组小鼠放入容器中,进气孔通入21%O2,持续3 h,1次/d,共3周,腹腔注射等量生理盐水。随后采用颈椎脱臼法处死小鼠,剪开胸腔,完整取出两肺,计数肺癌结节,免疫组化法检测HIF-1α表达,Western blot法检测HIF-1α、生存素(Survivin)和X联锁凋亡抑制蛋白(XIAP)的表达,RT-PCR法检测基质金属蛋白酶(MMP)-2和MMP-9的表达。结果与L组比较,余2组肺癌结节数增加,HIF-1α、Survivin、XIAP、MMP-2和MMP-9表达上调(P<0.05);与HL组比较,HLD组肺癌结节数增加,HIF-1α、Survivin、XIAP、MMP-2和MMP-9表达上调(P<0.05)。L组、HL组和HAD组分别见少量、中量和大量HIF-1α阳性细胞。结论右美托咪定可促进低氧肺癌小鼠肺癌细胞增殖,其机制与激活HIF-1α信号通路有关。

Objective To evaluate the effect of dexmedetomidine on hypoxia-inducible factor-1alpha(HIF-1α)signaling pathway during hypoxia in mice with lung cancer.Methods Eighteen clean-grade healthy adult male BALB/c nude mice,aged 8 weeks,weighing 20-30 g,were divided into 3 groups(n=6 each)using a random number table method:lung cancer group(group L),hypoxia+lung cancer group(group HL),and hypoxia plus lung cancer plus dexmedetomidine group(group HLD).Human lung adenocarcinoma A549 cell suspension 1×10^6/150μl was injected via the tail vein to establish the mouse model of lung cancer.After the model was established successfully,chronic intermittent hypoxia was performed as follows:the mice were placed in air-tight modular incubation chambers,and the atmosphere was controlled by a constant gas flow containing 10%O2 for 3 h once a day for 3 weeks.The mice in group HL were exposed to hypoxia.After the end of hypoxia exposure,the animals in group HLD were intraperitoneally injected with dexmedetomidine 25μg/kg 3 times a week for 3 weeks in total.The mice in group L were placed in air-tight modular incubation chambers and the atmosphere was controlled by a constant gas flow containing 21%O2 for 3 h once a day for 3 weeks,and the equal volume of normal saline was injected intraperitoneally.The mice were sacrificed by cervical dislocation,and the lung tissues were removed for determination of lung cancer nodules count,HIF-1αexpression(by immunohistochemistry),expression of HIF-1α,survivin and X chromosome linked inhibitor of apoptosis protein(XIAP)(by Western blot),and expression of matrix metalloproteinase-2(MMP-2)and MMP-9(by real-time polymerase chain reaction).Results Compared with group L,the number of lung cancer nodules was significantly increased,and the expression of HIF-1α,survivin,XIAP,MMP-2 and MMP-9 was up-regulated in the other two groups(P<0.05).Compared with group HL,the number of lung cancer nodules was significantly increased,and the expression of HIF-1α,survivin,XIAP,MMP-2 and MMP-9 was up-regulated in group HLD(P<0.05).A small number of HIF-1αpositive cells were found in group L,a medium number of HIF-1αpositive cells in group HL,and a large number of HIF-1αpositive cells in group HAD.Conclusion Dexmedetomidine can promote proliferation of tumor cells in mice with lung cancer during hypoxia,and the mechanism is related to activating HIF-1αsignaling pathway.