Effects Of Lidocaine On Lung Ultrastructure And Laminin In A Rat Modle Of LPS-induced Acute Lung Injury

ObjectiveTo study the effect of different dose of lidocaine on lung ultrastructure and laminin in rats of LPS-induced acute lung injury.MethodsThirty-two Wistar rats weighing 220-250g were randomly divided into 4 groups with 8 animals in each group: group I control(A); group II LPS (B); group III lidocaine 2mg/kg+LPS(C) and group IV lidocain 4mg/kg+LPS(D). ALI was induced by intravenous injection of LPS 2mg/kg in 1ml of normal saline over 20min.In the 2 pharmacological groups(groupIII,IV) different doses of lidocaine was injected i.v. over 40min followed by i.v. LPS. The animals were killed at 6h after LPS. The lung were immediately removed. The right lung was fixed with formalin, embedded in paraffin , sectioned at 5μm thick and stained with HE or by immunohistochemical method. The left lung was fixed with glutaraldehyde, made ultrathin section and examined under electron microscopy.ResultsLaminin was detected in all groups. LPS induced significant increase laminin expression in group II-IV. Lidocaine attenuated laminin expression induced by LPS in group III and IV , especially in group IV.The lung ultrasstructure was badly injuried in group II but in the two lidocaine groups(III,IV) the ultrastructural injury of the lung was greatly ameliorated. ConclusionLidocaine given before LPS can protect the lungs from ALI by. inhibiting excessive laminin expression in the lung.