目的 探讨细胞外信号调节激酶1/2（ extracellular signal- regulated kinases，ERK1/2）通路在内毒素休克大鼠肺脏内血红素氧合酶-1（Heme oxygenase-1，HO-1）表达过程中作用。 方法 清洁级雄性SD大鼠48只，体重180~200g，随机分为四组（n=12):假手术组（S组）、内毒素休克组（SS组）、内毒素休克+阻断剂组（SE组）和阻断剂组（E组）。S组和SS组股静脉输注0.1mlDMSO （二甲亚砜),SE组和E组股静脉ERK1/2阻断剂PD98059 10μmol/kg（溶于0.1mlDMSO）；30min后，S组和E组分别给予0.5ml生理盐水，SS组和SE组分别给予LPS（脂多糖）10mg/kg（溶于0.5ml生理盐水）， 连续监测平均动脉压（mean arterial pressure, MAP），2h内SS组和SE组MAP下降≥基础血压25%，认为模型制备成功。根据病理学切片、超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量评定肺损伤程度，应用荧光定量PCR技术和Western blot技术测定ERK1/2和HO-1的表达，判断ERK1/2通路在内毒素休克大鼠肺脏HO-1表达过程中的作用。结果 SS组的病理学评分( 4.50±2.14)、肺含水率(81.25±6.56)、MDA含量(3.12±1.30)明显高于S组（2.00±1.07 ）、（78.86±5.38 ）、（1.79±0.12）和E组（2.05±1.13）、（77.63±4.56）、（1.83±0.20）（P<0.05），但低于SE组（ 6.40±1.30）、（87.00±5.20）、（4.62±0.92）（P<0.05)；SS组SOD活性（20.2±2.4)明显低于S组(30.9±2.9)和E组(32.2±1.2)（P<0.05),但高于SE组( 14.9±3.2)(P<0.05);SS组ERK1/2蛋白（0.43±0.09）及p-ERK1/2蛋白（1.46±0.22）、HO-1mRNA（1.83±0.03）及HO-1蛋白（1.17±0.25）表达明显高于SE组、S组和E组（P<0.05）；上述指标在S组和E组之间无明显差异（P>0.05)。结论 内毒素休克大鼠给予ERK1/2通路的阻断剂后，肺损伤加重，其机制可能与ERK1/2被阻断后HO-1表达减少有关。
Objective To investigate the effect of ERK1/2 signaling pathway on expression of HO-1 on acute lung injury of endotoxic shock induced by lipopolysaccharide(LPS) in rats. Methods Forty-eight pathogen-free male SD rats weighing 180-200g were randomly divided into 4 groups (n=12 each):GroupⅠsham operation（group S）； GroupⅡ endotoxic shock （group SS); Group Ⅲ endotoxic shock and PD98059 (group SE)and GroupⅣ PD98059(group E). Rats in group S and group SS were administrated with DMSO 0.1ml intravenously; Rats in Group SE and group E were injected with the inhibitor of ERK1/2 （PD98059） in 0.1ml DMSO intravenously.30min later, Rats in Group S and group E received 0.5ml normal saline intravenously while rats in group SS and group SE received LPS10mg/kg in 0.5ml normal saline intravenously. Connected with arterial pressure monitor,if an initial 25% decrease in mean arterial pressure, the model can be put to use . The lung injury degree was judged by microscopic examination and moisture content and MDA content,SOD activity.The ERK1/2 protein、 p-ERK1/2 protein and HO-1 protein were measured by Western blot. HO-1mRNA level were measured by RT-PCR. Results The grade of the pathology( 4.50±2.14) ,MDA content(3.12±1.30), moisture content(81.25±6.56) in group SS were significantly higher than in group S （2.00±1.07 ）、（78.86±5.38 ）、（1.79±0.12）and group E（ 2.05±1.13）、（ 77.63±4.56）、（1.83±0.20）（P<0.05).but significantly lower than in group SE（ 6.40±1.30）、（87.00±5.20）、（4.62±0.92）（P<0.05);The SOD activity（20.2±2.4) in group SS were significantly lower than in group S(30.9±2.9) and group E(32.2±1.2)（P<0.05),but significantly higher than in group SE( 14.9±3.2)(P<0.05);ERK1/2 protein（0.43±0.09） and p-ERK1/2 protein （1.46±0.22）,HO-1mRNA （1.83±0.03）and HO-1 protein（1.17±0.25） in group SS were significantly higher than in group S, group SE and group E (P<0.05);And there were no significant difference in group S and group P among all the indexes(P>0.05). Conclusion Using the inhibitor of ERK1/2 signaling pathway in endotoxic shock rats enhanced lung injury ,and its mechanism may be related to decreased HO-1 expression by inhibition of ERK1/2 signaling pathway.
Cited
)
