The Preventive Effect Of DHA On Chemical Esophageal Stricture In Rats

Objective:To investigate the preventive effects and probable mechanisms of docosahexaenoic acid（DHA）on chemical esophageal stricture（CES）in rats.Methods:40 male SD rats of clean grade were randomly divided into 4 groups,including control group（DMSO group）,DHA whole course injection（DHA-W）group,DHA early injection（DHA-E）group and DHA delayed injection（DHA-D）group（n=10,respectively）.The rat CES model was established by the revised Yildiray Kalkan modeling method（D₀）,while the intervention drugs were intraperitoneally injected from5 days before（D-5）to 10 days after modeling operation（D9）.DMSO and DHA were injected during the whole course in DMSO group and DHA-W group,respectively.In DHA-E group and DHA-D group,DMSO was administrated from D_-5 to D_-1,and from D_-5 to D₄,respectively,while the DHA was injected D₀-D₉ and D₅-D₉,respectively.Rats were executed on D₁₀.The esophageal tissue was prepared for HE and Masson staining,while the hydroxyproline（Hyp）level in esophageal tissue and TNF-αand IL-6serum expression were detected by ELISA,and the expression of TGF-β1、Smad3 and Smad7 protein in esophageal tissue were detected by Western blot.Results:Esophageal stricture was found in only DMSO group.No significant difference was found in the survival rate,weight on D_-55 or D₅ among the groups（p>0.05）.The weight on D₉ in DMSO group was lower than that in other groups（p<0.05）,while no significant difference was found among the other groups（p>0.05）.The Hyp level,serum expression of TNF-αand IL-6,and TGF-β1 and Smad3 protein expression were found highest in DMSO group,while these in DHA-D group were higher than these in DHA-W group and DHA-E group（p<0.05）.Smad7 protein expression was found highest in DHA-W group,while that in DHA-D group was lower than that in DHA-W group and DHA-E group（p<0.05）.Conclusion:The esophageal chemical injury related esophageal stricture in rats could be effectively relieved by DHA intervention,which may associate with down-regulation of Hyp level in esophageal tissues,TNF-αand IL-6 level in serum,TGF-β1 and Smad3protein expression in esophageal tissues,as well as up-regulation of Smad7 protein expression.Immediately DHA intervention following esophageal injury may relate to a better protective effect on esophageal damage.