·论 著·

氢气对蛛网膜下腔出血致急性肾损伤大鼠的保护作用

宋京花,贾红艳,邵天鹏,柳志宝,赵元平

(河北省沧州市中心医院放射介入科,河北 沧州 061000)

[摘要] 目的探讨氢气对蛛网膜下腔出血(subarachnoid hemorrhage,SAH)致急性肾损伤(acute kidney injury,AKI)大鼠的保护作用。方法SPF级雄性Sprague Dawley(SD)大鼠,350~400 g,按随机数字表法分为对照组、模型组和氢气治疗组,每组12只大鼠。模型组和氢气治疗组采用大脑中动脉穿刺法和造影剂复合甘露醇输注模拟SAH模型;氢气治疗组大鼠在模型制备成功后24 h和48 h时置入预充2.9%浓度氢气的麻醉诱导箱中2 h作为氢气治疗,模型组置入预充空气的诱导箱;对照组除不刺破颅内血管外,其他操作均与模型组相同。在模型制备成功后72 h取主动脉血0.7~1.0 mL,检测尿素氮(blood urea nitrogen,BUN)和血肌酐(serum creatinine,SCr)水平。经心脏灌注后肾组织取材,采用苏木精-伊红染色法(hematoxylin-eosin staining,HE)观察大鼠肾脏病理变化;酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)测定大鼠肾脏组织活性氧簇(reactive oxygen species,ROS)水平;蛋白印迹法测定大鼠肾脏组织B淋巴细胞瘤2 (B-cell lymphoma-2,bcl-2)、bcl-2相关蛋k(bcl-2 associated-k,bak)及裂解的半胱氨酸蛋白酶3(cleaved caspase-3)蛋白表达;免疫荧光法测定大鼠肾脏细胞凋亡率;在细胞实验中采用300 μmol/L过氧化氢处理24 h肾小管上皮细胞(NRK52E)的方法制备氧化应激模型,干预后24 h、48 h分别用2.9%浓度氢气处理2 h,检测肾上皮细胞内丙二醛(malonaldehyde,MDA)和超氧化物歧化酶(superoxide dismutase,SOD)含量以及细胞凋亡率。 结果模型组和氢气治疗组大鼠BUN和SCr水平高于对照组,氢气治疗组大鼠BUN和SCr水平低于模型组(P<0.05)。模型组和氢气治疗组大鼠肾小管损伤评分高于对照组,氢气治疗组大鼠肾小管损伤评分低于模型组(P<0.05)。模型组和氢气治疗组大鼠肾脏组织bcl-2/bak蛋白比值低于对照组,cleaved caspase-3蛋白表达高于对照组;氢气治疗组大鼠肾脏大鼠肾脏组织bcl-2/bak蛋白比值高于模型组,cleaved caspase-3蛋白表达低于模型组(P<0.05)。模型组和氢气治疗组大鼠肾脏细胞凋亡率高于对照组,氢气治疗组大鼠肾脏细胞凋亡率低于模型组(P<0.05)。模型组和氢气治疗组肾小管上皮细胞MDA水平和凋亡率高于对照组,SOD水平和存活率低于对照组;氢气治疗组肾小管上皮细胞MDA和凋亡率低于模型组,SOD和存活率高于模型组(P<0.05)。结论氢气对SAH致AKI大鼠具有保护作用,其机制与氢气能减少ROS生成后抑制肾脏细胞凋亡有关。

[关键词] 蛛网膜下腔出血;急性肾损伤;氢气

蛛网膜下腔出血(subarachnoid hemorrhage,SAH)是最常见的脑血管意外之一,致死致残率较高[1]。既往研究表明,SAH患者1周内的全因病死率高达40%[2]。除疾病本身外,SAH的并发症也是导致其不良预后的重要因素。急性肾损伤(acute kidney injury,AKI)作为SAH患者常见的严重并发症之一,可显著增加SAH患者的病死率,因此,如何改善SAH合并AKI患者的肾脏功能是急需解决的医学难题之一[3]。氢气作为一种选择性抗氧化剂,具有易穿透细胞膜,可以作用于亚细胞结构,通过参与多种信号通路的调控,选择性清除机体内氧自由基的特点[4]。既往研究表明,氢气能选择性的清除的·OH和ONOO-等能导致细胞损伤的强氧化剂,从而产生抗炎,抗凋亡的作用[5]。已有研究证实,吸入低浓度氢气能减轻SAH大鼠神经元损伤,减轻局灶性脑缺血再灌注损伤[6]。但关于氢气对于SAH导致的远隔器官损伤的保护作用尚不明确,本研究旨在探讨氢气对SAH致大鼠AKI的肾脏功能的保护作用机制。

1 材料与方法

1.1 一般资料 53只SPF级Sprague Dawley雄性大鼠,8~9周龄,体重300~350 g,购自北京维通利华实验动物有限公司(SYXK(京)2012-0036)。所有大鼠饲养于动物房,室温维持在(25±1) ℃,湿度维持(55±5)%,光照/黑暗周期为12 h/12 h。所有大鼠手术前均分笼适应性饲养1周,所有大鼠在实验过程中均参考国家卫生研究院发布的《实验动物护理和使用指南》的建议接受人类护理。

1.2 主要设备与试剂 七氟醚购于上海恒瑞医药有限公司;甘露醇购于华仁药业(日照)有限公司;造影剂购于江苏恒瑞医药股份有限公司;ROS试剂盒,苯甲基磺酰氟,裂解液,bak兔多抗,caspase-3单克隆抗体,原位末端标记法(TdT-mediated dUTP Nick-End Labeling,TUNEL)试剂盒,PVDF膜,SDS-PAGE凝胶,预染彩虹maker,溴酚兰,QuickBlock封闭液,TBS-T,超敏ECL发光液,辣根过氧化物酶标记山羊抗兔IgG(H+L)均购于上海碧云天科技有限公司;苏木素,伊红染液购于珠海贝索生物技术有限公司;bcl-2兔多抗购于北京索莱宝科技有限公司;电泳槽购于北京君意东方电泳设备有限公司,型号:JV-ZY6;脱色摇床购于泰州诺米医疗科技有限公司,型号:NYC-80;多功能手术仪(双极电凝)购于武汉春光医疗美容仪器有限公司,型号:CHR-V;小动物麻醉机购于ABM;体温维持仪购于上海玉妍科学仪器有限公司,型号:XMTF-7000;离心机购于湖南安君研仪器有限公司,型号:A16K-R;酶标分析仪购于南京德铁实验设备有限公司,型号:HBS-1096B;荧光显镜购于广州市明美光电技术有限公司,型号:MF43。

1.3 动物实验

1.3.1 模型制备及验证 采用大鼠颈内动脉穿刺,输注甘露醇和造影剂的方法制备SAH致AKI模型。将大鼠置入预充七氟醚的麻醉箱进行麻醉诱导,待麻醉满意后仰卧位固定于铺有温毯的操作台上,设置肛温<38 ℃时温毯加热,3%~4%七氟醚麻醉维持。在模型制备前经鼠尾静脉采集血液测定血肌酐(serum creatinine,SCr)(0 h SCr),备皮、消毒、铺巾,正中切口,逐层分离,暴露左颈动脉,结扎离断颈外动脉分支并电凝止血。无损伤血管钳夹闭颈总动脉,颈内动脉。结扎颈外动脉远端并切开拉直,使得其与颈内动脉呈一直线。从颈外动脉将头端磨锐的尼龙线置入,直至有阻力感继续置入3 mm左右,刺破颈内动脉颅内段(20±2) mm,造成SAH,随后撤出尼龙线,结扎颈外动脉近心端,开放颈总动脉,缝合切口,并给予0.25%罗哌卡因局部封闭镇痛。随后从鼠尾静脉分别缓慢静注甘露醇9 g/kg,注入造影剂2 mL。对照组模型除不刺破大脑中动脉血管其余操作均相同。所有大鼠均回笼单独饲养。模型制备后24 h(24 h SCr)经鼠尾静脉采集血液测定SCr。24 h SCr>1.5×0 h SCr认为SAH致大鼠AKI模型制备成功。

1.3.2 实验分组 制备对照组12只,无死亡;制备SAH致AKI模型使用大鼠41只,死亡8只,SAH致AKI模型(24 h SCr>1.5×0 h SCr)成功24只,随机分为模型组(n=12)和氢气治疗组(n=12)。制备模型成功后24 h和48 h时,将氢气治疗组大鼠置入预充2.9%浓度氢气的麻醉诱导箱中2 h,将模型组和对照组大鼠置入预充空气的诱导箱2 h。

1.3.3 AKI血清学参数分析 各组大鼠在组织灌注前,从主动脉采集血样0.7~1.0 mL,测定BUN和SCr水平。

1.3.4 苏木精-伊红染色法(hematoxylin-eosin staining,HE)测定大鼠肾脏病理改变 模型制备成功后72 h,在6%七氟醚深度麻醉下,迅速去除胸骨打开胸腔,充分暴露心脏,于心尖处取血2 mL,随后使用连接输液器的穿刺针从心尖部位插入,向上进针到升主动脉并使用血管钳固定。剪开右心耳后使用生理盐水灌注,直至肝,肾和肺脏颜色转白,右心耳流出的液体清亮后,灌注10%甲醛250 mL,摘取右肾(n=6)。经固定、脱水、透明、浸腊、包埋后,切制5 μm石蜡切片。经二甲苯Ⅰ、Ⅱ分别浸泡10 min后,不同浓度梯度酒精(100%,90%,80%,70%)脱蜡,各2 min,随后置入苏木素染液中染色6 min,水化30 min后置入伊红染色液中染色3 min,水洗2 min后置入不同浓度梯度酒精(70%、80%、90%、100%)脱水,各30 s,再放入二甲苯Ⅰ、Ⅱ中分别透明10 min,滴加中性树胶后封片,观察。肾脏病理评分依据Paller评分法:即每高倍镜视野随机选择10个有病变的肾小管,按100个肾小管记分,肾小管明显扩张、细胞扁平记1分;刷状缘损1分,脱落记2分;肾小管管腔内有脱落的、坏死的细胞包括未成管型或细胞碎片记1分,管型记2分。

1.3.5 肾脏组织活性氧(reactive oxygen species,ROS)水平的测定 模型制备成功后72 h,在8%七氟醚麻醉下摘取右肾,将0.1 mL含1 mg肾脏皮质组织、2.9 mL ROS分析介质和15 nmol/L 2′,7′-二氯氟二乙酸混匀后,在37 ℃温箱中孵育15 min,酶标仪测定488 nm激发波长,525 nm发射波长下的荧光值。

1.3.6 蛋白印迹法测定大鼠肾脏组织B淋巴细胞瘤2 (B-cell lymphoma-2,bcl-2)、bcl-2相关蛋k(bcl-2 associated-k,bak)以及裂解的半胱氨酸蛋白酶3(cleaved caspase-3)蛋白表达 模型制备成功后72 h,每组取6只大鼠的肾脏组织100 mg(n=6)。充分剪碎、研磨组织,加入500 μL苯甲基磺酰氟和500 μL裂解液进行组织匀浆,在4 ℃,12 000 r/min,半径=8 cm条件下离心5 min,取上清采用二喹啉甲酸法测定蛋白含量。计算含30 μg蛋白的溶液体积即为上样量,加入上样缓冲液后于水中煮沸5 min至蛋白变性,加入10% SDS-PAGE凝胶上样孔中,恒压80 V电泳至预染彩虹预染蛋白分离清晰,溴酚兰即将跑出凝胶。随后采用80 V恒压湿转50 min,将蛋白转至聚偏二氟乙烯膜,随后移至含有封闭液的平皿中,室温下脱色摇床上摇动封闭1 h。TBS-T缓冲液洗涤聚偏二氟乙烯膜后,分别加入bcl-2(1∶1 000),bak(1∶1 000),caspase-3(1∶1 000)一抗,4 ℃过夜。TBS-T洗膜3次,每次5 min。加入辣根过氧化物酶标记山羊抗兔IgG(H+L)(1∶1 000)室温下孵育1 h。TBS-T缓冲液洗膜3次每次5 min。加入ECL发光液,在脱色摇床上反应5 min,发光仪显影。GAPDH作为内参蛋白,以目的蛋白与内参蛋白条带的灰度比值表示蛋白表达水平。

1.3.7 免疫荧光法测定大鼠肾脏细胞凋亡率 每组取6只大鼠的肾脏石蜡切片(n=6),在二甲苯Ⅰ、Ⅱ各浸泡10 min以及不同浓度梯度酒精(100%、90%、80%、70%)脱蜡后,置于装有PBS的染色缸中洗片3次,每次5 min。滴加20 μL不含DNase的蛋白酶K,于37 ℃温箱中孵育反应35 min,置于装有PBS的染色缸中洗片3次,每次5 min。随后加入TUNEL检测液,在37 ℃温箱中避光孵育60 min,置于装有PBS的染色缸中洗片3次,每次5 min,滴加含DAPI的封片液,盖玻片封片,荧光显微镜下进行观察。计算TUNEL/DAPI双阳性细胞数占总细胞的百分比即为细胞凋亡率,计数5个高倍视野取平均值。

1.4 细胞实验

1.4.1 肾小管上皮细胞的培养及分组 肾小管上皮细胞系NRK52E用含10%胎牛血清的DMEM培养基,于37 ℃、5% CO2恒温箱培养,每天换液1次,待细胞融和至90%,加入胰蛋白酶进行消化传代,取对数生长期细胞用于实验;模型组用300 μmol/L过氧化氢干预24 h建立氧化应激损伤模型,氢气治疗组在过氧化氢干预后24 h和48 h分别给予2.9%氢气处理2 h。

1.4.2 肾小管上皮细胞丙二醛(malonaldehyde,MDA)和超氧化物歧化酶(superoxide dismutase,SOD)测定 待细胞干预结束后取各组细胞培养基1 mL,按照试剂盒说明书要求处理样品,硫代巴比妥酸法检测MDA,黄嘌呤氧化法检测SOD,按照试剂盒步骤操作。每次设3个复孔,重复3次。

1.4.3 流式细胞仪检测肾小管上皮细胞凋亡水平 各组细胞干预后培养2 d,添加0.25%胰蛋白酶后收集各组细胞,用150 μL缓冲液将各组细胞悬浮,添加Annexin V-FITC约10 μL后,避光孵育15 min。添加5 μL PI均匀混合,继续添加150 μL缓冲液,立即用流式细胞仪检测细胞凋亡率,每次设3个复孔,重复3次。

1.4.4 四甲基偶氮唑蓝(Methyl Thiazolyl Tetrazolium,MTT)法检测细胞存活率 各组细胞接种于96孔板上,每孔避光加入5 g/L的MTT溶液20 μL,继续孵育 4 h。弃去培养液,每孔加入二甲基亚砜150 μL,于微量振荡器上水平缓慢振荡1 min,待充分结晶沉淀后,用酶联检测仪检测波长570 nm处的吸光度(optical delnsity,OD)值,计算存活率=实验组OD值/对照组OD值×100%。

1.5 统计学方法 应用SPSS 17.0统计软件分析数据。计量资料比较采用单因素方差分析和Tukey检验。P<0.05为差异有统计学意义。

2 结 果

2.1 氢气治疗对大鼠BUN和SCr水平的影响 模型组和氢气治疗组大鼠BUN和SCr水平高于对照组,氢气治疗组大鼠BUN和SCr水平低于模型组,差异有统计学意义(P<0.05)。见表1。

表1 各组大鼠BUN和SCr水平比较
Table 1 Comparison of blood urea nitrogen and
serum creatinine of rats in each group

组别 BUN(mmol/L)SCr(μmol/L)对照组 8.18±3.9479.49±22.99模型组 35.40±7.89∗234.33±37.77∗氢气治疗组26.95±5.48∗#166.41±29.69∗#F值 64.84376.453P值 <0.001<0.001

*P值<0.05与对照组比较 #P值<0.05与模型组比较(Tukey 检验)

2.2 氢气治疗对大鼠肾脏病理改变的影响 HE染色结果显示:对照组大鼠肾脏组织结构清晰,细胞排列紧密,细胞核及细胞质染色均匀,仅见少量肾小管上皮细胞刷状缘。模型组大鼠肾脏组织可见大量小管上皮细胞肿胀、颗粒及空泡变性;部分小管上皮细胞刷状缘、扁平、皱缩、脱落、核深染、裸露,严重部位见弥漫性细胞片状崩解、坏死,脱落,基底膜不完整;部分肾小管管腔扩张,管腔内可见上皮细胞碎片,肾间质水肿,充血及出血明显。氢气治疗组组织肾小管肿胀、充血、出血及细胞核脱落情况明显减轻(图1)。模型组和氢气治疗组大鼠肾小管损伤评分高于对照组,氢气治疗组大鼠肾小管损伤评分低于模型组,差异有统计学意义(P<0.05)。见表2。

图1 各组大鼠肾脏组织HE染色(×100)

A.对照组;B.模型组;C.氢气治疗组

Figure 1 HE staining of renal tissue of rats in each group(× 100)

表2 各组大鼠肾小管损伤评分比较
Table 2 Comparison of renal tubular injury of
rats in each group 分)

组别 肾小管损伤评分对照组 0.50±0.55模型组 3.50±0.55∗氢气治疗组2.00±0.63∗#F值 40.500P值 <0.001

*P值<0.05与对照组比较 #P值<0.05与模型组比较(Tukey 检验)

2.3 氢气治疗对大鼠肾脏组织中ROS水平的影响 模型组和氢气治疗组大鼠肾脏组织中ROS水平高于对照组,氢气治疗组大鼠肾脏组织中ROS水平低于模型组,差异有统计学意义(P<0.05)。见表3。

表3 各组大鼠肾脏组织ROS水平比较
Table 3 The content of ROS in the renal tissue of
rats in each group

组别 ROS对照组 17.31±0.47模型组 23.84±0.43∗氢气治疗组20.08±0.49∗#F值 312.880P值 <0.001

*P值<0.05与对照组比较 #P值<0.05与模型组比较(Tukey 检验)

2.4 氢气治疗对大鼠肾脏组织中bcl-2、bak和cleaved caspase-3蛋白表达的影响 模型组和氢气治疗组大鼠肾脏组织bcl-2/bak蛋白比值低于对照组,cleaved caspase-3蛋白表达高于对照组;氢气治疗组大鼠肾脏组织bcl-2/bak蛋白比值高于模型组,cleaved caspase-3蛋白表达低于模型组,差异有统计学意义(P<0.05)。见图2,表4。

图2 各组大鼠肾脏组织bcl-2、bak、cleaved caspase-3和内参的蛋白印记

Figure 2 Western blots of bcl-2, bak, cleaved caspase-3 and GADPH in the renal tissue of rats in each group

表4 各组大鼠肾脏组织bcl-2/bak比值和cleaved
caspase-3蛋白表达比较
Table 4 Comparison of bcl-2/bak ratio and cleaved
caspase-3 expressions in the renal tissue of
rats in each group

组别 bcl-2/bak比值cleaved caspase-3对照组 100.14±7.9211.14±2.28模型组 82.35±10.05∗27.09±6.25∗氢气治疗组138.62±12.09∗#18.21±2.28∗#F值 48.07423.247P值 <0.001<0.001

*P值<0.05与对照组比较 #P值<0.05与模型组比较(Tukey 检验)

2.5 氢气治疗对大鼠肾脏细胞凋亡率的影响 模型组和氢气治疗组大鼠肾脏细胞凋亡率高于对照组,氢气治疗组大鼠肾脏细胞凋亡率低于模型组,差异有统计学意义(P<0.05)。见表5。

表5 各组大鼠肾脏细胞凋亡率比较
Table 5 Apoptotic rate of renal cells of rats in each group

组别 肾脏细胞凋亡率对照组 1.24±0.60模型组 15.72±2.48∗氢气治疗组6.17±2.24∗#F值 84.607P值 <0.001

*P值<0.05与对照组比较 #P值<0.01与模型组比较(Tukey 检验)

2.6 氢气治疗对氧化应激肾小管上皮细胞MDA、SOD、存活率和凋亡率的影响 模型组和氢气治疗组肾小管上皮细胞MDA水平和凋亡率高于对照组,SOD水平和存活率低于对照组;氢气治疗组肾小管上皮细胞MDA和凋亡率低于模型组,SOD和存活率高于模型组,差异有统计学意义(P<0.05)。见表6。

表6 各组肾小管上皮细胞MDA、SOD、凋亡率和存活率比较
Table 6 Comparison of malondialdehyde,superoxide dismutase,apoptotic rate,and survival rate of tubular epithelial cells in each group

组别 MDA(μmol/mg)SOD(U/mg)凋亡率(%)存活率(%)对照组 12.07±1.8745.82±3.1210.38±2.40100.00 模型组 53.61±5.46∗9.83±106∗44.54±3.82∗72.64±5.40∗ 氢气治疗组29.70±6.65∗#28.96±4.86∗#26.95±3.39∗#87.19±4.82∗#F值 168.173253.238247.24564.338P值 <0.001<0.001<0.001<0.001

*P值<0.05与对照组比较 #P值<0.05与模型组比较(Tukey 检验)

3 讨 论

SAH是一种严重威胁人类生命健康的急危重症,其中85%出血原因为颅内动脉瘤破裂,临床上主要表现为颅内压升高、患者意识减退甚至消失[7]。目前认为早期脑损伤是SAH致死致残的主要原因,其病理生理机制主要包括动脉瘤破裂后的机械性损伤、颅内压升高、脑血流量降低、脑灌注压下降、大脑皮质广泛去极化、细胞凋亡和坏死自噬作用、离子稳态破坏、炎症反应、血脑屏障破坏等[8-10]。早期脑损伤在损伤神经功能的同时,也导致了全身应激反应、炎症反应以及神经体液改变等,进而导致心脏、肺、肾及胃肠道等远隔器官的损伤[11-12]。甘露醇作为降低颅内压既经济又有效的药物,常应用于SAH患者,造影剂是SAH介入诊断及治疗的必备药,两者的应用均可加重肾脏负担。本研究参考文献[13]通过颈外动脉置管,经颈内动脉刺破大脑中动脉,制备SAH模型,并在造模成功后经鼠尾静脉给予甘露醇及造影剂,模拟了SAH患者的入院诊治过程,将24 h SCr高于1.5倍基础 SCr定为AKI。本研究结果表明,SAH大鼠应用造影剂及甘露醇后,肾功能受损,AKI发生率约为70%,提示SAH诱发的大鼠AKI模型建立成功。

既往研究表明,SAH早期诱发的儿茶酚胺大量释放,导致外周器官缺血缺氧,并诱发多种炎性因子活化;SAH可诱发脑血管痉挛,缺氧后的脑组织造成线粒体能量耗竭,多种氧离子及过氧化氢生成,血脑屏障完整性下降,炎性因子及氧自由基释放入血,进一步加重全身炎性反应[14]。肾脏作为血流量最大的外周远隔器官之一,SAH诱发的AKI是临床中最为常见的并发症之一,已有研究表明,SAH诱发的AKI可能与小管上皮细胞氧化应激、炎症反应,进一步诱导肾小管上皮细胞凋亡反应有关[15]。线粒体作为氧化应激反应的主要靶点,缺血再灌注损伤可导致ROS水平急剧升高,诱导凋亡因子bak活化,导致线粒体外膜通透性增强,进而诱发细胞凋亡;bcl-2作为最重要的抗凋亡因子,通过抑制bak活化,保持线粒体膜完整性,抑制细胞凋亡[16]。既往研究表明,bcl-2/bak比值的改变可调控细胞凋亡,bcl-2/bak比值下调,表明细胞正在发生凋亡[17]。caspase-3作为凋亡级联反应的最后一级,活化后裂解为cleaved caspase-3,通过进入细胞核切割DNA,诱发细胞凋亡[17]。本研究结果显示,SAH后大鼠肾脏组织ROS水平升高,bcl-2/bak比值下调,cleaved caspase-3表达上调,肾脏组织细胞凋亡率升高,SCr、BUN及肾损伤评分升高,提示了SAH相关性AKI与氧化应激后诱发肾小管上皮细胞凋亡相关。

氢气作为一种无色无味不易溶于水的气体,近年来被发现其具有强大的抗氧化作用;与其它吸入性治疗药物比较,具有易扩散、起效快、无明显不良反应等优点[18]。Jiang等[19]报道,吸入2%氢气能选择性清除·OH和ONOO-,减轻脑缺血再灌注引起的氧化应激损伤;Kumagai等[20]研究表明,氢气通过抑制线粒体生成过氧化物,显著减轻SAH诱发的神经细胞凋亡。本研究通过模拟SAH诱发的AKI型,在SAH后24 h、48 h时吸入2.9%氢气2 h进行治疗,结果显示,氢气治疗组SCr、BUN及损伤评分减低,表明氢气对SAH诱发的AKI具有保护作用;氢气显著减少了肾组织中的ROS含量,bcl-2/bak比值上调,肾脏细胞凋亡率降低,cleaved caspase-3表达下调,表明,氢气对SAH诱发AKI的保护作用与减轻氧化应激,抑制肾细胞凋亡相关。

为了进一步证实氢气对SAH诱发AKI的保护作用,本研究采用过氧化氢处理肾小管上皮细胞的体外模型,结果显示,与单纯过氧化氢处理肾小管上皮细胞比较,氢气可显著降低过氧化氢处理的肾小管上皮细胞中的MDA水平,并增加SOD水平,同时肾小管上皮细胞凋亡率显著降低。表明氢气减轻SAH诱发AKI的机制与其抑制氧化应激减少肾小管上皮细胞凋亡相关,与Ming等[21]的研究结果一致。

综上所述,氢气对SAH致AKI大鼠具有保护作用,其机制与氢气能减少ROS产生,减少氧化应激,上调bcl-2/bak比值从而抑制肾脏细胞凋亡有关。

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Protective effects of hydrogen gas on acute kidney injury induced by subarachnoid hemorrhage in rats

SONG Jing-hua, JIA Hong-yan, SHAO Tian-peng, LIU Zhi-bao, ZHAO Yuan-ping

(Department of Interventional Radiology, Cangzhou Central Hospital, Hebei Province, Cangzhou 061000, China)

[Abstract] Objective To explore the protective effects and mechanism of hydrogen gas against acute kidney injury(AKI) induced by subarachnoid hemorrhage(SAH) in rats. Methods SPF-grade male Sprague Dawley(SD) rats(weighing 350-400 g), were divided into control group(n=12), model group(n=12) and hydrogen treatment group(n=12) according to random number table method. In the model and hydrogen treatment group, SAH was induced by endovascular perforation combined with contrast agent and mannitol transfusion. At 24 h and 48 h after successful SAH modeling, the rats in the hydrogen treatment group were placed into anesthesia induction box filled with 2.9% hydrogen for 2 h, but the rats in the model group were only placed into the induction box filled with air. The rats in the control group were treated in the same fashion as model group except that the intracranial vessels were not punctured. At 72 h after SAH, 0.7-1.0 mL of blood samples was collected from aorta to measure the levels of blood urea nitrogen(BUN) and serum creatinine(SCr). After sampling via cardiac perfusion, the pathological changes of kidney, reactive oxygen species, expressions of B-cell lymphoma-2(bcl-2), bcl-2 associated-k(bak) and cleaved caspase-3, renal apoptosis were assessed by hematoxylin eosin staining, enzyme linked immunosorbent, western blot and TdT-mediated dUTP Nick-End Labeling(TUNEL) assays, respectively. In the cell experiment, renal tubular epithelial cells(NRK52E) were treated with 300 μmol/L hydrogen peroxide for 24 h to prepare an oxidative stress model. At 24 h, 48 h after intervention, the cells were treated with 2.9% hydrogen gas for 2 h. Then the contents of malondialdehyde(MDA), superoxide dismutase(SOD), and apoptotic rate of renal epithelial cells were detected. Results The levels of BUN and SCr were higher in the model group and hydrogen treatment group than in the control group, which, however,were lower in hydrogen treatment group than in the model group(P<0.05). The renal tubule injury scores were higher in the model group and hydrogen treatment group than in the control group, which, however, were lower in hydrogen treatment group than in the model group(P<0.05). The ratio of bcl-2/bak protein in renal tissues of rats was lower, while the expression of cleaved caspase-3 was higher in the model group and hydrogen treatment group, as compared with those in the control group; the ratio of bcl-2/bak protein in renal tissues of rats was higher, while the expression of cleaved caspase-3 was lower in hydrogen treatment group, as compared with those in the model group(P<0.05). The renal apoptosis significantly higher in the model group and hydrogen treatment group than in the model group, which was lower in hydrogen treatment group than in the model group(P<0.05). In vitro, compared with control group, the MDA level and apoptosis rate of renal tubular epithelial cells were increased, but the SOD level and survival rate were decreased in the model group and hydrogen treatment group; the MDA level and apoptosis rate of renal tubular epithelial cells were lower, but the SOD level and survival rate were higher in the hydrogen treatment group, as compared with those in the model group(P<0.05). Conclusion Hydrogen gas exhibits a protective effect against SAH-induced AKI in rats, and the mechanism may be associated with the inhibition of ROS-induced renal cell apoptosis under hydrogen treatment.

[Key words] subarachnoid hemorrhage; acute kidney injury; hydrogen

doi:10.3969/j.issn.1007-3205.2021.06.002

[中图分类号] R743.35

[文献标识码] A

[文章编号]1007-3205(2021)06-0624-07

[收稿日期]2020-10-21

[基金项目]沧州市科学技术发展计划(172302117)

[作者简介]宋京花(1974-),女,河北沧州人,河北省沧州市中心医院主管护师,医学学士,从事放射介入研究。

(本文编辑:赵丽洁)