The Effects Of Lidocaine On Surfactant-associated Protein–a Expression In Rats Alveolar Epithelial TypeⅡ Cells And Its Mechanism

Objective: The purpose of our experiment is to investigate the effects of Lidocaine onsurfactant-associated protein-A in rats Alveolar epithelial type Ⅱ cells and its mechaism.Method:Alveolar epithelial type.Ⅱ cells were isolated from the lung of anesthetizedadult male Sprague-Danley（SD） rats（200-250g）,purified,incubated and identifide.the cells were randomly divided into8groups:group I:control（C）, groupII: Forskolin,theAC activato（rF）, group III: Lidocaine2μg/m（lL₁）, groupIV: Lidocaine20μg/ml（L₂）, group V: Lidocaine200μg/ml（L₃）, group VI: the PKAinhibitor H89＋L₁（P＋L₁）；group VII：PKAinhibitor H89＋L₂（P＋L₂）；group VIII：PKA inhibitor H89＋L₃（P＋L₃）。 The cells culture incubations were performed after theabove-mentioned medicines were added.And after6hr、12hr or24hr of culture,the cAMPcontent, the PKA activity,the expression of SP-AmRNA and SP-A in each group weremeasured respectivetly.Results:①The cAMP content, the PKA activity,the expression of SP-AmRNA andSP-A were enhanced in group II in6hr、12hr or24hr as compared with controlgroup（P<0.05）.②There is no significant differences in group III、IV or V as comparedwith control group during the period cultured for6h（rP>0.05）,whereas the cAMP content,the PKA activity,the expression of SP-AmRNA and SP-A were elevated in group III、IVor V after the cells were cultured for12hr or24hr and the higher the concentration is,the clearer becomes;the values in group III、IV or V in24hr were more higher thanin12hr （P<0.05）.③There is no significant differences in group VI、VII、 VIII、in6hr as compared with group III、IV、V in6h（rP>0.05）；the cAMP content was heightenconsistent and the PKA activity,the expression of SP-AmRNA and SP-A weredecreased in group VI、VII、 VIII as compared with group III、IV、V in12hr or24hr（P<0.05）.Conclusion: Lidocaine can enhance the expression of SP-AmRNA and SP-A in ratsAECⅡ，the higher concentration and the longer time,the more likely the effects areevident;The mechanism maybe related to that:The effects of Lidocaine onsurfactant-associated protein-AmRNA in rats AECⅡ were taken effect by activatingcAMP-PKA signaling pathway.