The Effect Of Dietary N-6:n-3Polyunsaturated Fatty Acid Ratio On Chronic Reflux Esophagitis In Rats And Its Potential Mechanism

Background and objective: Reflux esophagitis (RE) is one of the typical lesions ofGastroesophageal reflux disease (GERD). The incidence of GERD is thought relatingto high fat diet, while the ratio of dietary n-6: n-3polyunsaturated fatty acid (PUFAs)is believed to play a role in the regulation of the inflammatory process. This studywas aimed to investigatethe effect of dietary n-6: n-3PUFAs ratio on chronic RE in arat model and the relationship with lipid peroxidation.Methods:Forty rats were randomly divided into4groups according to the n-6:n-3PUFAs ratios in feed, including1:1.5,10:1,5:1and pure n-6PUFAs groups, and asham operation group (10rats, which were fed with pure n-6PUFAs) was set up asblank control.Rat RE model (Pyloric Nylon Loop-induced Chronic Acid RefluxEsophagitis) was established by pyloric clip and section ligation. After14daystreatment, mucosachanges of the esophagus were determined, and and the expressionof IL-1β, IL-8, TNFα protein and mRNA in esophageal tissue homogenatewereevaluated by Western blot and RT-PCR, respectively, while the MDA and SODlevels were evaluated by ELISA, respectively.Results: The food intake and body weights in the rats showed no significantdifference before operation(p>0.05), while those were reduced in all groups exceptsham group in postoperative d7(p<0.05) and were recovered in d14, and nointergroup differences were found (p>0.05). In PUFA1:1.5,PUFA5:1,PUFA10:1, n-6PUFA groups and sham operation group, the postoperative d14survival rates were70%,60%,80%,70%and100%, respectively (p=0.306). The degree ofesophagitiswas lower in PUFA1:1.5group when compared to that in the other modelgroups(p<0.05), but no significant difference was found amongPUFA5:1,PUFA10:1and n-6PUFA groups(p>0.05).The protein and mRNA expressionof IL-1β, IL-8and TNFα, and the MDA levels were increased in all model groups when compared to that in sham group(p<0.05), which showed a rising tendency fromPUFA1:1.5,PUFA5:1,PUFA10:1groups to n-6PUFA group. The SOD levels weredecreased in all model groups when compared to that in sham group(p<0.05), whichshowed a reducing tendency from PUFA1:1.5,PUFA5:1,PUFA10:1groups to n-6PUFAgroup.Conclusion: The results indicate that the reflux related esophageal mucosal damagecould be lighten by adding more n-3PUFAs in diet, which was associated with anup-regulation of antioxidant activity and a down-regulation of lipid peroxidation inesophageal epithelium.Dietary n-6/n-3PUFAs ratio reduction may be a beneficialstrategyfor gastroesophageal reflux disease management.