Possible Molecular Mechanisms Of Iron-induced Cardiac Apoptosis And Fibrosis And Effects Of Iron Chelator

Background: According to statistics, there are the more than100millionpatients with iron overload in the world. Iron overload cause cardiovasculardamage and other related diseases, which is closely associated withcardiovascular mortality and morbidity. Previous study of iron is about irondeficiency, the hotspot of recent research is about iron overload and cellapoptosis. Data show that iron overload reactive oxygen species (ROS)significantly increased, leading myocardial apoptosis and fibrosis. Iron overloadwhen applied iron chelating agent can effectively alleviate these changes,becoming the focus in our study.Objective: This study aimed by studying the expression of myocardialapoptosis and fibrosis and the interference of iron overload and iron chelatingagent and detection of apoptosis related proteins caspase-3, caspase-9contentchanges in gerbils myocardial cells. To clarify molecular mechanism ofmyocardial cell apoptosis induced iron overload, providing a new method ofprevention and treatment of the cardiovascular injury disease caused by Ironoverload.Methods: Select4-6weeks old healthy male30Mongolian gerbils,randomly divided into5groups.10weeks the control group (C),10weeks the iron load group (IO),3months the control group (C-3m),3months the notreatment after iron load group (IO-3m),3months the treatment after iron loadgroup (IO-DFR). Gerbils after weighing, do the ECG examination via chest wallline under light anesthesia. Then put to death in rats, and take its hearts andweigh, cutting it into three parts. Apex of myocardial is used for tissue proteinextraction content to detect iron deposit; Middle part for histochemical staining,application of three kinds of dyeing technology combines TUNEL staining anddystrophin immunohistochemical and DAPI, detecting of myocardial cellapoptosis and cytoskeleton form change, at the same time, application of picricacid-Sirius red staining the collagen content of measuring heart tissue clearance,observing increasing myocardial apoptosis and fibrosis by iron overload;Bottom part adopts Western blot technique to detect content of myocardial tissueapoptosis related proteins Caspase-3and Caspase-9, in order to make clearwhether iron overload causes myocardial cell apoptosis and intervention effectof iron chelating agent.Results:1. The control group (C-3m) gerbils ECG is normal; Iron overload group(IO-3m) gerbils ECG Lead II shows P wave tip, atrial premature beats,ventricular premature beat and electrocardiogram abnormalities; That ironoverload group (IO-3m) gerbils shows right atrial hypertrophy, arrhythmia,myocardial injury; Iron+a griddle; bring it mixture group (IO+DFR-3m) showsno obvious abnormal electrocardiogram. 2. Iron overload group (IO, IO-3m) iron concentration in gerbil myocardialtissue is significantly higher than the control group (CON, CO-3m), thedifference was statistically significant (P<0.01); iron chelating agentintervention group (IO+DFR3m) iron content in myocardial tissue in ironoverload group significantly decreased, and the results show significantdifference (P <0.01).3. Iron overload group (IO, IO-3m) iron concentration in gerbil myocardialtissue is significantly higher than the control group (CON, CO-3m), thedifference was statistically significant (P<0.01); iron chelating agentintervention group (IO+DFR3m) serum iron concentration decrease, thedifference was statistically significant (P <0.01).4. Compared to no iron gerbils (C-3m), the iron load of group (IO-3m)gerbils myocardial Caspase-319kda, Caspase-317kda content significantlyincreased, iron load by the iron chelating agent treatment group3months after(IO-DFR) were decreased; Compared to no iron gerbils (C-3m), the iron load ofgroup (IO-3m) gerbils myocardial Caspase-919kda, Caspase-917kda contentsignificantly increased, iron load by the iron chelating agent treatment group3months after (IO-DFR) were decreased;5. Blank control group (CON), only a very small amount of iron deposits.Iron overload group (IO-3m) gerbils myocardial cytoplasm to clear a lot of irondeposits, iron chelating agent intervention group (IO+DFR-3m) iron depositiondecreased significantly. 6. Blank control group (CON) myocardial cell have a small amount ofcollagen fiber, mainly distributed around the blood vessels; Compared to controlgroup, iron overload group (IO-3m) collagen fiber quantity increased obviouslybetween myocardial cell, crisscrossed and disordered arrangement. The ironoverloaded group of collagen content increased by291%; iron chelating agentintervention group (IO+DFR3m) the amount of collagen fibers than ironoverload group decreased by53%.7. Compared with the control group (CON), iron overload group (IO-3m)of myocardial cell apoptosis positive cells was significantly increased (1475%).Iron chelating agent intervention group (IO+DFR3m) on the number ofmyocardial cell apoptosis decreased significantly (74%).Conclusion:1. Iron overload gerbils appear arrhythmia, myocardial tissue Caspaseapoptosis related proteins in Caspase-319kda,,Caspase-317kda and Caspase-940/38kda, Caspase-917kda fragment content increased obviously, the contentof myocardial cell iron deposit and the collagen fiber is increased;2. Iron chelating agent intervention group reduce arrhythmia, myocardialtissue Caspase apoptosis related proteins in Caspase-319kda,,Caspase-317kdaand Caspase-940/38kda, Caspase-917kda fragment content significantlydecreased, reducing the content of myocardial cell iron deposit and collagenfibers.