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皮质醇导致脓毒症大鼠TNF-α释放增加
http://www.100md.com 《中国病理生理杂志》 1999年第6期
     作者:宋新明 王吉甫 赵继宗 詹煌南

    单位:宋新明 广州军区广州总医院普外科 (广州 510010);王吉甫 赵继宗 詹煌南 中山医科大学附一院外科

    关键词:炎症;氢化可的松;肿瘤坏死因子;白介素-6

    皮质醇导致脓毒症大鼠TNF 摘 要 目的:探讨皮质醇对脓毒症大鼠TNF-α、IL-6释放的影响及其临床意义。方法:SD大鼠58只,分为5组,A、C组于盲肠结扎穿孔CLP后每12 h皮下注射氢化可的松(30 mg/kg),B、D组于CLP后同时点注等量生理盐水,E组为对照组。A、B组于48 h,C、D组于24 h处死,测定血及腹水中TNF-α、IL-6含量和血中皮质醇水平。结果:A组死亡3例,余各组无死亡。A组血浆皮质醇和TNF含量均显著高于B、C、D、E组(P<0.05)。A、B、C、D组腹腔液中TNF-α含量显著高于E组(P<0.05)。所有大鼠腹腔液中TNF-α、IL-6含量均显著高于血浆(P<0.05)。结论:脓毒症时, 应用皮质醇可使血浆TNF-α含量升高,且随作用时间延长TNF-α升高愈显著,并伴有动物死亡率增加。但对血浆及腹腔液中IL-6含量无显著影响。
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    Cortisol lead to increment of TNF-α release in septic rats

    SONG Xin-Ming, WANG Ji-Fu, ZHAO Ji-Zong ZHAN Huang-Nan

    General Surgery Department, Guangzhou General Hospital of PLA, Guangzhou , ( 510010)

    Abstract AIM: To investigate the effects of cortisol on the levels of TNF-α and IL-6 in sepsis in rats with cecal ligation performation (CLP) model and its clinic significance. METHODS: 58 SD rats were divided into 5 groups. Rats in Group A and C were performed with CLP model and injected with hydrocortisone at 12h intervals. Rats in group B and D were performed with CLP model and injected with normal saline at 12h intervals. Those in group E (the control group) were performed with laparotomy without CLP and were injected with NS at the same time points. Animals were killed at different points(group C & D at 24 h, and group A, B& E at 48 h) after CLP or sham laparotomy. Samples of blood and ascitic fluid were collected for measurements of TNF-α,IL-6 and cortisol. RESULTS: 1.The cortisol level in group A was significantly higher than that in group C (P<0.01).The cortisol level in plasma of group B,D and E was undetectable. 2.The average level of TNF-α in plasma in group A was significantly higher than that in group B,C,D and E(P<0.05). TNF-α in ascitic fluid was detectable in all groups and that in group A,B,C and D was significantly higher than that in group E (P<0.05).TNF-α and IL-6 levels in ascitic fluid were significant higher than that in plasma in all groups (P<0.01). 3. No significant differences in IL-6 level were found in plasma and ascitic fluid between A,B,C ,D and E groups (P>0.05). CONCLUSION: Treatment to septic rats with cortisol made a significant increase of TNF-α level in plasma. Animals with elevated TNF-α level had a higher rate of death.
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    MeSH Inflammation; Hydrocortisone; Tumor necrosis factor; Interleukin-6

    虽然糖皮质激素在创伤、炎症、休克时有抑制炎性介质生成和释放的作用[1],但迄今尚无资料显示糖皮质激素对炎性细胞因子有明显的抑制作用。临床上应用皮质激素治疗严重感染或脓毒症也未取得确切疗效。为此,我们采用大鼠盲肠结扎穿孔(cecal ligation perforation,CLP)脓毒症模型,观察皮质醇对脓毒症大鼠细胞因子TNF-α和IL-6释放的影响及可能的治疗作用。

    材料和方法

    动物分组:二级SD大鼠58只、体重155~210 g,由中山医大动物中心提供,分为A、B、C、D、E 5组,每组雌雄各半。A组:(CLP48h+hydrocortisone)14只,CLP术毕即刻及每12 h皮下注射氢化可的松(hydrocortisone 江苏扬州制药厂)30 mg/kg,观察48 h;B组:(CLP48 h+NS)14只,CLP术毕即刻及每12 h皮下注射等量生理盐水6 ml/kg,观察48 h;C组:(CLP24 h+hydrocortisone)10只,模型制作及氢化可的松应用同A组,仅观察24 h;D组:(CLP24 h+NS)10只,模型复制及生理盐水注射同B组,观察24 h;E组为对照组,10只,不复制CLP模型,仅行开腹术。术毕即刻及每12 h皮下注射等量生理盐水6 ml/kg,观察48 h 。
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    模型复制参照Flammand等[2]的方法。实验前动物禁食12 h,自由饮水,用戊巴比妥钠(40 mg/kg ip)麻醉,无菌操作,腹正中切口2 cm进腹,于盲肠出口处用4号线结扎,14 G套管针将盲肠贯通穿孔一次,穿孔为两个,还纳肠管于腹腔,间断缝合腹壁。A组1例、B组3例因麻醉死亡,不纳入实验观察,动物置22 ℃恒温消毒间饲养,自由进食进水。C、D组于24 h,A、B、E组于48h心脏穿刺采血活杀。开腹采集腹腔液,血及腹水均采用肝素20 U/mL抗凝,3000 r/min 离心10 min分离上清-70 ℃冻存,备测TNF-α、IL-6和皮质醇含量。

    皮质醇测定采用放射免疫法(RIA)(北京北方生物技术研究所)单位nmol/L;TNF-α 采用ELISA方法(BioSource,美国);IL-6采用ELISA方法(Genzym,美国)。统计处理采用非参数方差分析、配对资料t检验和非参数相关分析,由SPSS统计软件处理,数据以1.gif (164 bytes)表示。
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    结果

    A组3例于24~36 h死亡,死亡率为23%(3/13),B、C、D、E组在观察时间内均无死亡。A组血浆皮质醇水平为(53.5±32.2) nmol/L(n=10);C组血浆皮质醇水平为(38.7±19.3) nmol/L(n=10),统计处理显示A组血浆皮质醇水平显著高于C组(P<0.01)。B、D、E 3组血浆均检测不出皮质醇含量。

    一、TNF-α含量分析(表1):

    表1 脓毒症大鼠 TNF-α含量分析

    Tab 1 The content of TNF-α in plasma(P) and peritoneal fluid(PF) in septic rats (ng/L, n=8)

    A
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    B

    C

    D

    E

    P-TNF-α

    22.5±19.7#

    4.5±8.8

    5.8±10.0

    0

    0

    PF-TNF-α

    397.6±279.7▲**
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    194.1±189.3▲*

    254.8±158.5▲**

    194.0±161.7▲**

    16.9±5.5**

    # P<0.05,vs B,C,D,E groups; ▲ P<0.05,vs E group; *P<0.05,** P<0.01, vs P-TNF-α in same group

    Group:A=GLP 48h+hydrocortisone (H); B=CLP48h+NS; C=CLP24h+H; D=CLP24h+NS; E=control

    每组测定8例血浆和腹腔液TNF-α含量,A组7例,B组2例,C组4例血浆中能检测出TNF-α含量, D组和E组无1例检测出TNF-α含量。TNF-α阴性者以0 ng/L计算,采用非参数方差分析,发现A组血浆中TNF-α含量显著高于B、C、D、E 4组(P<0.05)。B、C、D、E组间无显著差异(P>0.05)。腹腔液中均能检测出TNF-α含量,A、B、C、D 4组腹腔液中TNF-α含量显著高于E组(P<0.05),但A、B、C、D组间无显著差异(P>0.05),所有大鼠腹腔液中TNF-α含量均显著高于血浆TNF-α含量(P<0.01)。
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    二、IL-6含量分析(表2):

    表2 脓毒症大鼠 IL-6含量分析

    Tab 2 The content of IL-6 in plasma(P) and peritoneal fluid(PF) in septic rats (ng/L, n=8)

    A

    B

    C

    D

    E

    P-IL-6

    8.5±4.7

, http://www.100md.com     7.5±1.8

    6.7±1.1

    6.0±1.5

    PF-IL-6

    25.5±8.5**

    23.5±3.3**

    24.1±10.0**

    23.3±7.2**

    30.7±5.9**

    **P<0.01,vs P-IL-6 in same group
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    所有大鼠血浆和腹腔液均能检测出IL-6,A、B、C、D、E 5组间血浆及腹腔液中IL-6含量均无显著差异(P>0.05),但各组腹腔液中IL-6含量均显著高于血浆中IL-6含量(P<0.01)。

    讨论

    CLP是研究脓毒症的典型模型,它是由盲肠梗阻并严重腹膜炎而引发全身炎症反应,即脓毒症状态。CLP模型伴有细胞因子的改变[3]

    本研究发现,应用氢化可的松(30 mg/kg)作用于脓毒症大鼠48 h,血浆皮质醇水平显著高于其它组,并伴有TNF-α含量显著升高及动物死亡数增加。氢化可的松作用48 h,TNF-α检出率为87.5%,作用24 h,TNF-α检出率为50%,而未用氢化可的松的B组和D组检出率分别为25%和0。大鼠血浆中高水平的皮质醇对应有高TNF-α含量,B组和D组未能检测出皮质醇含量,其TNF-α的检出率也极低。用氢化可的松治疗的A组,在48 h观察期内死亡3例,死亡率为23%,而B组未采用氢化可的松治疗,同样观察48小时,无1例死亡。有脓毒症的大鼠腹腔液中TNF-α含量较对照组显著升高,以氢化可的松治疗的A组和C组升高更加明显。结果表明,在脓毒症状态下,氢化可的松有促进TNF-α产生和释放的作用,并促进脓毒症大鼠的死亡。腹腔液中TNF-α含量显著高于血浆中含量,说明TNF-α既参与全身性炎症反应,更参与局部炎症反应。
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    脓毒症状态下,高TNF-α含量伴有高死亡率,说明TNF-α参与脓毒症的病理生理过程。早期研究表明TNF-α能引起内毒素样休克和多器官组织损伤[4],进一步研究表明TNF-α对机体的损伤作用有赖于感染或内毒素的存在[5,6]。可见在脓毒症状态下,由于内毒素的大量存在,促进TNF-α产生和释放的因素都会增加脓毒症的死亡率。皮质激素能刺激TNF-α的产生和释放,而且随激素应用时间延长TNF-α含量越高,动物的死亡数增加。从细胞因子的角度,应用皮质激素治疗脓毒症对机体将产生有害影响。Molijn等[7]也认为,脓毒症状态下,大剂量的糖皮质激素治疗是有害的。

    本研究发现各组间血浆及腹水IL-6的含量无显著差异。一方面说明皮质激素对IL-6的产生和释放无明显的抑制或促进作用。另一方面也说明IL-6是一个急性应激反应因子,它的变化与测定时间关系密切。本实验IL-6测定时间分别为48 h和24 h,已明显超过急性应激6~8 h IL-6达至高峰的时间。Ertel等[3]也报道CLP模型后2~10 h IL-6活性显著升高,20 h则明显回落。提示这种升高并非脓毒症引起,可能系手术本身的创伤所致。CLP模型组和对照组腹腔液中IL-6含量均显著高于血浆中IL-6含量,但各组间无显著差异。说明腹部损伤和腹腔内感染均可使局部IL-6显著升高,但这种上升幅度与感染程度并不相关。
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    参考文献

    1 金惠铭.肿瘤坏死因子.见:崔乃杰,刘兵主编.实用危重病急救医学. 天津:天津科技翻译出版公司,1993.53~88.

    2 Flammand FJ, Sibbald WJ, Girotti MJ, et al. Pentoxifylline does not prevent microvascular injury in normotensive, septic rats. Crit Care Med, 1995, 23:119.

    3 Ertel W, Morrison MH, Wang P, et al. The complex pattern of cytokines in sepsis, association between prostaglandins, cachectin, and interleukins. Ann Surg, 1991, 214:141.
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    4 Tracey KJ, Beutler B, Lowry SF, et al. Shock and tissue injury by recombinant human cachectin. Science, 1986, 234:470.

    5 宋新明,白涛, 吴伟斌等. 肿瘤坏死因子对大鼠器官功能损伤的实验研究. 中国危重病急救医学, 1994,6:75.

    6 Neilson IR, Neilson KA, Junis EJ, et al. Failure of tumor necrosis factor to produce hypotensive shock in the absence of endotoxin. Surgery, 1989, 106:439.

    7 Molijn GJ, Spek JJ, van-Uflelen JC, et al. Differential adaption of glucocorticoid sensitivity of peripheral blood mononuclear leukocytes in patients with sepsis or septic shock. J Clin Endocrinol Metab, 1995, 80:1799.

    (1998年9月2日收稿,1999年1月29日修回), 百拇医药