亚精胺减轻脂多糖诱导的小鼠急性肺损伤

目的　观察亚精胺（spermidine）对脂多糖（LPS）诱导的急性肺损伤（ALI）的影响。 方法　采用5 mg/kg的LPS经气管滴注，建立ALI小鼠模型。用小动物呼吸机检测亚精胺对ALI小鼠呼吸功能的影响；观察亚精胺对ALI小鼠肺组织形态变化的影响；检测ALI小鼠支气管肺泡灌洗液（BALF）中总蛋白、总细胞数及中性粒细胞数目，并检测髓过氧化物酶（MPO）的水平；qPCR检测ALI小鼠肺组织中TREM-1 mRNA的表达；ELISA检测ALI小鼠BALF中sTREM-1的蛋白水平。 结果　亚精胺可改善ALI小鼠的呼吸功能；减轻LPS诱导的肺部病理损伤；减少蛋白渗出和中性粒细胞浸润；降低ALI小鼠肺内炎症放大受体TREM-1的表达。 结论　亚精胺能减少炎症细胞浸润，抑制炎症因子表达，从而减轻LPS诱导的ALI，其机制可能与亚精胺可抑制ALI小鼠肺组织TREM-1表达有关。

Spermidine alleviates acute lung injury induced by lipopolysaccharide in mice

Objective To observe the effects of spermidine on acute lung injury (ALI) induced by lipopolysaccharide (LPS). Methods ALI mice model was established by intratracheal drip of LPS ( 5 mg/kg ) . Effects of spermidine on respiratory function of ALI mice were detected by small animal ventilator, the effects of spermidine on lung tissue morphology of ALI mice were observed. The total protein, total cell number and neutrophil number in bronchoalveolar lavage fluid (BALF) of ALI mice were detected, and the level of myeloperoxidase (MPO) was tested. The expression of TREM-1 mRNA in lung tissue of ALI mice was detected by qPCR, and the protein level of sTREM-1 in BALF of ALI mice was measured by ELISA. Results Spermidine could improve the respiratory function of ALI mice, alleviate LPS-induced lung pathological damage, decrease protein exudation and neutrophil infiltration, and reduce the expression of TREM-1, an inflammatory amplification receptor in the lungs of ALI mice. Conclusions Spermidine may reduce the infiltration of inflammatory cells, inhibit the expression of inflammatory factors and alleviate LPS-induced ALI. The mechanism may be related to the inhibition of TREM-1 expression in lung tissue of ALI mice by spermidine.