丹酚酸B对脂多糖诱导的小鼠急性肺损伤的影响及机制研究

Effect of salvianolic acid B on lipopolysaccharide‑induced acute lung injury in mice and its underlying mechanisms

目的探究丹酚酸B在脂多糖(lipopolysaccharide,LPS)诱导的小鼠急性肺损伤(acute lung injury,ALI)中的作用及可能机制。方法采用随机数字表法将18只健康成年雄性C57BL/6小鼠分为3组(每组6只):假手术组(Sham组)、LPS组、LPS+丹酚酸B组(LPS+SAB组)。予LPS组和LPS+SAB组小鼠气管内注射10 mg/kg LPS,Sham组气管内注射等体积PBS;经过上述处理,LPS+SAB组即刻经尾静脉注射50 mg/kg丹酚酸B,Sham组和LPS组经尾静脉注射等体积PBS。12 h后通过H⁃E染色观察肺组织病理改变,使用BCA法检测支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中总蛋白浓度,ELISA法检测BALF中TNF⁃α、IL⁃6和IL⁃1β浓度,Western blot法检测肺组织丝裂原激活的蛋白激酶(mitogen⁃activated protein kinase,MAPK)和NF⁃κB信号通路中p38、c⁃Jun氨基端激酶(c⁃Jun⁃N⁃terminal kinase,JNK)、胞外信号调节激酶(extracellular signal⁃regulated ki⁃nase,ERK)、p65蛋白及其磷酸化蛋白水平,使用丙二醛(malondialdehyde,MDA)和超氧化物歧化酶(superoxide dismutase,SOD)试剂盒分别检测肺组织中MDA和SOD含量。结果与Sham组比较:LPS组和LPS+SAB组小鼠肺损伤评分,BALF中总蛋白浓度及TNF⁃α、IL⁃6、IL⁃1β浓度,肺组织中p⁃p38/p38、p⁃JNK/JNK、p⁃ERK/ERK、p⁃p65/p65,肺组织中MDA含量均升高(P<0.05);LPS组和LPS+SAB组肺组织中SOD含量降低(P<0.05)。LPS+SAB组小鼠肺损伤评分,BALF中总蛋白浓度及TNF⁃α、IL⁃6、IL⁃1β浓度,肺组织p⁃p38/p38、p⁃JNK/JNK、p⁃ERK/ERK、p⁃p65/p65,肺组织中MDA含量均低于LPS组(P<0.05);LPS+SAB组SOD含量高于LPS组(P<0.05)。结论丹酚酸B可通过抑制肺组织炎症蛋白激活和氧化应激,从而减轻LPS诱导的小鼠ALI严重程度。

Objective To investigate the role and possible mechanism of salvianolic acid B in lipopolysaccharide(LPS)⁃in⁃duced acute lung injury(ALI).Methods A total of 18 healthy adult male C57BL/6 mice were divided into three groups according to the random number table method(n=6):a sham operation(Sham)group,a LPS group,and a LPS+salvianolic acid B(LPS+SAB)group.Mice in the LPS group and the LPS+SAB group were intratracheally injected with 10 mg/kg LPS,while those in the sham group were in⁃tratracheally injected with an equal volume of phosphate buffered saline(PBS).After intratracheal administration,the LPS+SAB group was immediately injected with 50 mg/kg salvianolic acid B via the tail vein,while the sham group and the LPS group were injected with an equal volume of PBS via the tail vein.After 12 h,hematoxylin⁃eosin(H⁃E)staining was used to observe the pathological changes of lung tissue.The total protein concentrations of bronchoalveolar lavage fluid(BALF)were detected by bicinchoninic acid(BCA)method.The levels of tumor necrosis factor⁃α(TNF⁃α),interleukin(IL)⁃1βand IL⁃6 in BALF were detected by enzyme linked immunosorbent assay(ELISA).The levels of p38,c⁃Jun⁃N⁃terminal kinase(JNK),extracellular signal⁃regulated kinase(ERK),p65 and their phosphory⁃lated proteins in the mitogen⁃activated protein kinase(MAPK)and nuclear factor⁃κB(NF⁃κB)signaling pathways in lung tissues were detected by Western blot.The contents of malondialdehyde(MDA)and superoxide dismutase(SOD)in lung tissues were detected by MDA and SOD kits.Results Compared with the sham group,the LPS group and the LPS+SAB group presented increases in lung injury scores,total protein concentrations in BALF,the levels of TNF⁃α,IL⁃6 and IL⁃1βin BALF,the levels of p⁃p38/p38,p⁃JNK/JNK,p⁃ERK/ERK,p⁃p65/p65 and MDA content in lung tissue(P<0.05)as well as decreases in SOD content in lung tissues(P<0.05).Com⁃pared with the LPS group,the LPS+SAB group showed decreases in lung injury scores,the total protein concentration in BALF,the lev⁃els of TNF⁃α,IL⁃6 and IL⁃1βin BALF,the levels of p⁃p38/p38,p⁃JNK/JNK,p⁃ERK/ERK and p⁃p65/p65 and MDA content(P<0.05),as well as increases in SOD content in lung tissues(P<0.05).Conclusions Salvianolic acid B may inhibit the activation of inflam⁃matory proteins and oxidative stress,so as to attenuate LPS⁃induced ALI in mice.