Study On Expression Level Changes Of Axon Guidance Cues Slit2and Robo4in Lung Tissue Of Rat With Acute Lung Injury

Objective: To observe changes of Slit2and Robo4expression level in rat withacute lung injury(ALI) induced by cecum ligation and puncture(CLP) to exploremechanism of Slit2and Robo4in pathogenesis of ALI.Methods: Seventy-two Sprague-Dawley rats were randomly divided into controlgroup(n=24) and ALI group(n=48).ALI model was reproduced by CLP.The controlgroup only experienced a simulated operation without CLP.Both groups were furtherdivided respectively into12h,24h,48h subgroups after operation,each subgroup ofcontrol group had eight rats,each subgroup of ALI group had sixteen rats.Partialpressure of oxygen in arterial blood(PaO2),lung tissue wet/dry weight(W/D)ratio,lunghistopathologic changes,pulmonary microvascular permeability were observed.Theexpression of Slit2and Robo4mRNA were detected by reversetranscription-polymerase chain reaction(RT-PCR).The serum tumor nocrosisfactor-α(TNF-α)and interleukun-6(IL-6) were measured with enzyme linkedimmunosorbent assay(ELISA).The expression of Slit2and Robo4protein in lungtissues was assessed by immunohistochemistry.Results:Compared with the control group,in ALI rats at different time points, PaO2decreased significantly,lung W/D weight ratio， pulmonary microvascularpermeability,the serum TNF-α and IL-6increased significantly(all P＜0.05),histopathology of lung revealed signs of injury.After injury,expression of Slit2mRNA and Slit2protein in lung tissue decreased markedly(P＜0.05respectively).butthere were no significant difference in expression of Robo4mRNA and Robo4proteinin lung tissue between ALI group and control group(P>0.05respectively).Conclusion: Lung tissues of normal rats express Slit2and Robo4.The decreased Slit2mRNA and protein expressions in the lung tissue of rat with ALI caused by CLPmay be associated with the occurrence of ALI.