Effects Of Restraint Stress On Iron Metabolism In Intestinal And Liver Of Rats

Iron is one of the essential trace elements in animal organisms.It works as an important components of hemoglobin,myoglobin,and various enzymes and participates in material metabolism and energy metabolism.Iron metabolism disorder can cause growth inhibition and various iron metabolism related diseases,affecting animal survival rate,lactation,weight,etc.It is harmful for production efficiency and economic losses in livestock.It has also been reported that stress induces iron homeostasis disorder,but its mechanism remains controversial.Therefore,in this experiment,a non-invasive restraint stress model was used to simulate animal setbacks and anxiety in daily growth to investigate the changes and mechanisms of iron metabolism in the duodenum and liver of rats under restraint stress.1.Effects of restraint stress on growth performance and related indexes of iron metabolism in ratsIn order to examine the effect of restraint stress on growth performance and iron metabolism,24 7-week Sprague Dawley male rats were randomly divided into control group(the control group,Con)and bound groups(restraint group,RS).Rats of RS group were shackled 6 h daily(9:00-15:00)continuously for 14 d.Rats were fasted and water banned during the trial operation.The rat's weight,feed intake,and daily gain was recorded to measure the growth performance of rats.Blood,duodenum,liver,and spleen were collected at the end of experiment.Organ index,blood routine parameters,plasma corticosterone,and iron metabolism indices were determined to evaluate the effect of restraint stress on iron metabolism in rats.The experimental results showed that compared with Con group,the daily feed intake,daily gain and daily iron intake in the RS groups were significantly decreased(P<0.05),but the final body weight in the RS group was unchanged(P>0.05)and he percentage of mononuclear cells in the RS group was increased(P<0.05)and the unsaturated iron binding capacity was decreased in the RS group(P<0.05),and no significant changes in plasma iron content,transferrin binding iron,total iron binding capacity,transferrin saturation,RBC and platelet related indicators in the RS group(P>0.05).Compared with Con group,the RS group had lower liver weight and spleen weight(P<0.05),and enhanced the hepatic iron content(P<0.05).All the results suggest that restraint stress reduces the growth rate and the iron intake of rats without affecting the utilization of iron by red blood cells and circulating iron metabolism,but it may hinder the development of liver and spleen and induce liver iron.accumulation.2.The effect of restrain stress on iron metabolism of duodenum and liver in ratsTo investigate the restrain stress on iron metabolism of duodenum and liver in rats,Intestinal and hepatic morphology were observed using HE staining.Prussian blue staining was used to evaluate the duodenal and hepatic iron distribution.qPCR and western blot were conducted to examine the expression of iron metabolism-related genes and proteins expression.The results showed that restraint stress resulted in the loss or congestion of intestinal villi in rats.Prussian blue staining showed that the iron staining granules increased in the liver of rats conducted by restraint stress,indicating that restraint stress induced hepatic iron overload.Restraint stress had no significant effect on genes and proteins expression related to iron metabolism in rat's duodenum(P>0.05).Restraint stress enhanced the expression of transferrin(Tf)and ransferrin receptor 2(TfR2)proteins,which was closely associated with hepatic iron uptake,but decreased their mRNA expression in the liver(P<0.05).MiRDB and TargetScan predicted 10 microRNAs targeted Tfr2 in rats,but restraint stress had no significant effect on the expression of 10 microRNAs(P>0.05).The results suggest that restraint stress has no significant effect on iron absorption in rat duodenum,but may induce iron accumulation in rat liver through TfR2-mediated iron uptake pathway,and the high expression of TfR2 is not achieved through post-transcriptional regulatory mechanisms.In conclusion;restraint stress inhibits rat's food intake and iron intake in rats,reduced the growth rate of rats,induced liver iron accumulation,but did not affect the use of iron by the body's red blood cells and circulating iron metabolism.Restraint-induced liver iron accumulation is associated with high expression of Tf and TfR2 proteins,which involved in hepatic iron uptake.