摘要:
目的 探讨苏拉明(suramin)对脂多糖(lipopolysaccharide,LPS)诱发小鼠急性肺损伤的防治作用及其分子机制.方法 24只健康清洁级雄性C57BL/6小鼠以随机数字法分为生理盐水对照组和苏拉明治疗组,分别于生理盐水和苏拉明处理后静脉注射LPS(5 mg/kg)建立肺损伤模型,并于造模后0h、24h及72 h,取肺组织进行苏木精-伊红染色(HE染色)评估生理盐水对照组和苏拉明治疗组的肺脏病理损伤程度;采用RT-PCR检测肺组织中肿瘤坏死因子(TNF-α)和白介素-6 (IL-6) mRNA的表达水平.体外分别用生理盐水和苏拉明处理人单核细胞白血病细胞(THP-1细胞株)后,给予100 ng/mL LPS刺激,建立体外脓毒症模型,应用Western Blot法检测LPS刺激后10 min、20 min、30 min细胞内丝裂原活化蛋白激酶(mitogen activated protein kinase,MAPK)信号转导通路关键分子ERK1/2、JNK及P38蛋白的磷酸化水平.组间数据比较采用独立样本t检验分析,P <0.05为差异具有统计学意义.结果 与生理盐水对照组相比,苏拉明可明显减轻LPS对小鼠(72 h)肺组织的损伤程度(生理盐水组,3.90 ±0.35;苏拉明组,2.50 ±0.12)(t =7.668,P<0.01),且显著性降低LPS处理24 h后肺组织TNF-α的表达水平(生理盐水组,8.35±1.63;苏拉明组,4.62±0.70)(t=4.187,P<0.01)和IL-6 mRNA的表达水平(生理盐水组,10.53±2.10;苏拉明组,5.53±1.10)(=4.224,P<0.01);苏拉明可显著下调LPS刺激THP-1细胞后10 min、20 min及30 min胞内MAPK信号通路ERK1/2、JNK、P38蛋白的磷酸化水平.结论 苏拉明对LPS诱发的肺损伤具有保护作用,其下调促炎因子表达的机制可能与抑制单核细胞MAPK通路的活化有关.%Objective The purpose of this research is to study the preventive and therapeutic effects of suramin on lipopolysaccharide (LPS)-induced mouse model of acute lung injury and its molecular mechanism.Methods A total of 24 healthy male C57BL/6 mice were randomly divided into two groups: Control group and suramin group.LPS (5 mg/kg, iv) induced acute lung injury model was used in this study.The severity of lung injury was evaluated using haematoxylin-eosin (HE) staining after the injection of LPS for 0, 24 and 72 hours.The expression of TNF-α and IL-6 mRNA levels were also detected by RT-PCR.In vitro, THP-1 cells were stimulated by LPS (100 ng/mL) with saline or suramin pre-treatment.The expressions of p-ERK1/2, p-JNK and p-P38 were analyzed by Western blot at 10 min, 20 min and 30 min after LPS insult.A 2-tailed Student's t test was used to compare difference between two independent groups.Results Compared with the saline group, the lung tissues injury were significantly decreased in the suramin group of 72 hours after the injection of LPS (saline 3.90 ±0.35;suramin 2.50 ±0.12) (t =7.668, P < 0.01).The expressions of TNF-α (saline 8.35 ± 1.63;suramin 4.62 ± 0.70) (t =4.187, P<0.01) andIL-6 (saline10.53 ± 2.10;suramin5.53±1.10) (t=4.224, P<0.01) mRNA were also obviously reduced in suramin group after the injection of LPS for 24 hours.The expression levels of pERK1/2, p-JNK and p-P38 were obviously down-regulated by suramin at 10 min, 20 min and 30 min after LPS stimulation.Conclusion Suramin protected LPS-induced acute lung injury through down-regulating the expression of pro-inflammatory factors, which was closely relative to the inhibition of the MAPK pathway.