三羟异黄酮保护内毒素诱导急性肺损伤实验研究

Protective effect of genistein on endotoxin-induced acute lung injury in rats

目的探讨三羟异黄酮对内毒素(LPS)诱导急性肺损伤(ALI)的保护作用及作用机制。方法将32只大鼠随机分为4组(每组8只):生理盐水组(S组)、三羟异黄酮组(G组)、LPS组(L组)和三羟异黄酮预处理组(G+L组)。LPS刺激后,观察6 h。以肺湿干重比(W/D)和支气管肺泡灌洗液(BALF)蛋白含量作为肺损伤的指标。通过检测髓过氧化物酶(MPO)活性及BALF中细胞学分析来评估中性粒细胞的聚集和活性。采用RT-PCR,检测ICAM-1mRNA在肺组织表达的变化。肺组织经HE染色后,观察组织病理学上的改变。结果L组大鼠BALF总蛋白和W/D都较对照组明显升高(P<0.01);同S组比较,在G+L组LPS导致了BALF、肺组织匀浆MPO活性及BALF中PMN数目显著增加(P<0.01);L组大鼠肺组织中ICAM-1mRNA表达水平显著高于S组(P<0.01)。预先给予三羟异黄酮可以非常显著抑制LPS引起这些指标的改变(P<0.05或0.01)。三羟异黄酮预处理也改善了LPS所致肺组织形态学上严重的损伤。上述所有参数在G组与S组间差异无统计学意义。结论三羟异黄酮预处理能够减轻LPS诱导的大鼠急性肺损伤。这种效果可能与其下调ICAM-1的表达而抑制PMN在肺组织的聚集、激活有关。

Objective To investigate th proteetive effect of genistein on endotoxin-induced acute lung injury in rats,and explore the underlying mechanisms.Methods Thirty-two male Sprague-Dawley rats were randomly divided into four experimental groups;saline control （S）,genistein alone（G）,lipopolysaccaride（LPS） alone（L）,and genistein pretreatment （G＋L）.Each treatment group consisted of eight animals.Animals were observed for 6h after LPS ehallenge,and the wet/dry（E/D） weight ratio of the lung and the protein contents of the bronchoalveolar lavage fluid （BALF） were nsed as indexes of lung injury.Neutrophil recruitment and activation were evaluated by BALF cellularity and myeloperoxidase （MPO） aetivity.RT-PCR analysis was performed with lung tissue to assess the gene expression of ICAM-1.The histopathologic changes were also observed nsing the H＆E stains of lung tissue.Results Lung injury parameters,including the wet/dry weight ratio and protein comtent in BALF,were significantly higher in the L group than in the S group（P〈0.01）;In the L group,higher numbers of neutrophils and greater MPO activity in cell-free BAL and lung homogenates were observed when compared with the S group （P〈0.01）.There was a marked inerease in lung ICAM-1 mRNA in response to LPS challenge（P〈0.01,L group versus S group）.Genistein pretreatment significantly attenuated LPS-induced changes in all above parameters（P〈0.05 or 0.01）.LPS caused extensive morphologic lung damage,which was also reduced after genistein pretreatment.All the above-parameters of the G group were not significantly different from those of the S group.Conclusions Genistein pretreatment attenuated LPS-induced lung injury in rats.This beneficial effect of genistein may be due to,in part,the inhibition of neutrophilic recruitment and activity possibly through the inhibition of lung ICAM-1 expression.