The Study Of Ketanserin On The Improvement Of Heart Function In Rats With Heart Failure

Objective:Heart failure,also known as heart dysfunction,is a clinical syndrome caused by cardiac dysfunction and a shortage of ventricular filling and ejection capacity.Its main clinical manifestations include dyspnea,fatigue,limited exercise tolerance and fluid retention,etc.With the improvement of living standard and the development of aging population,the morbidity and mortality of heart failure is distinctly increasing.Ketanserin is a selective 5-HT_2A receptor antagonist,which also has weak antagonism to H and receptor.It is mainly used for the treatment of hypertension and Raynaud's disease.Our preliminary study showed that ketanserin could improve the arterial baroreflex?ABR?function without changing the blood pressure in rats.We found in the study that the ABR function in rats with acute myocardial ischemia was significantly lower than that of normal rats.Compared with arterial baroreflex-normal rats?ABR-NRs?,arterial baroreflex-deficient rats?ABR-DRs?had more serious myocardial injury after acute miocardial infarction?MI?.Based on these results,we hypothesized that ketanserin,the tool drug to improve the function of ABR,should have the effect of improving the cardiac function in rats with heart failure.We screened ketanserin 1 mg/kg as the most suitable dose to improve cardiac function by acute myocardial ischemia.Then we mainly focused on the intuitive protective effect of ketanserin against heart failure.We studied the therapeutic effect of ketanserin in two heart failure models in rats.Echocardiography,cardiac hemodynamics,cardiac weight index,blood biochemistry,myocardial pathology and long-term survival time were recorded in this study to clarify the effect of ketanserin on heart failure rats.This research can provide initial data for further study and also bring some new ideas for the treatment of heart failure.Methods:We firstly made acute MI model by SD rats to observe the changes of BRS,blood pressure and heart rate before and after acute MI.We used ABR-DRs and its control ABR-NRs to observe the effect of low ABR function on myocardial injury in rats with acute MI.Then we used different dose of ketanserin to observe the improvement of ABR function and cardiac function and we found the optimal dose of ketanserin to improve the cardiac function.We made two heart failure models: Model One was induced by the ligation of left anterior descending coronary artery and Model Two was induced by receptor antagonist,which also has weak antagonism to H and receptor.It is mainly used for the treatment of hypertension and Raynaud's disease.Our preliminary study showed that ketanserin could improve the arterial baroreflex?ABR?function without changing the blood pressure in rats.We found in the study that the ABR function in rats with acute myocardial ischemia was significantly lower than that of normal rats.Compared with arterial baroreflex-normal rats?ABR-NRs?,arterial baroreflex-deficient rats?ABR-DRs?had more serious myocardial injury after acute miocardial infarction?MI?.Based on these results,we hypothesized that ketanserin,the tool drug to improve the function of ABR,should have the effect of improving the cardiac function in rats with heart failure.We screened ketanserin 1 mg/kg as the most suitable dose to improve cardiac function by acute myocardial ischemia.Then we mainly focused on the intuitive protective effect of ketanserin against heart failure.We studied the therapeutic effect of ketanserin in two heart failure models in rats.Echocardiography,cardiac hemodynamics,cardiac weight index,blood biochemistry,myocardial pathology and long-term survival time were recorded in this study to clarify the effect of ketanserin on heart failure rats.This research can provide initial data for further study and also bring some new ideas for the treatment of heart failure.Methods: isoproterenol injection combined with cold water stimulation.We observed the effect of ketanserin on cardiac function in two models.Specific experiments are as follows:Experiment One: effect of low ABR function on myocardial injury in rats.1.The changes of BRS,blood pressure and heart rate in SD rats after acute MI.Male SD rats were divided into 2 groups with 10 rats in each group.One group was used for acute MI model made by ligation of left anterior descending coronary artery and the other was sham group.The BRS?baroreflex sensibility?,SBP?systolic blood pressure?,DBP?diastolic blood pressure?and HR?heart rate?were measured seven days later and the difference between the two groups was compared.2.Comparison of injury degree of ABR-DRs and ABR-NRs after acute MI.The male ABR-DRs and ABR-NRs were two months old?²00 g?.The ligation of left anterior descending coronary artery was conducted to observe the difference of injury degree in two groupsExperiment Two: determine the optimal dose of ketanserin on heart function in rats with acute MI.1.The effect of different dose of ketanserin on BRS,blood pressure and heart rate in arterial baroreflex-deficient rats?ABR-DRs?.ABR-DRs are spontaneous low ABR function rats bred by our department.Its baroreflex sensitivity?BRS?is low?BRS<0.6 ms/mmHg?and the blood pressure is normal.It is a good model to measure the effect of drugs on BRS.Twent y-four male ABR-DRs?²20g?were randomly divided into three groups.0.3 mg/kg,1 mg/kg and 3 mg/kg ketanserin was administrated to rats by gavage after their base value of BRS,SBP,DBP and HR was detected.Thirty minutes later the value of BRS,SBP,DBP and HR were detected again to compare the changes.2.Effect of different dose of ketanserin on cardiac function in rats with acute MI.Twent y-five male Sprague-Dawley?SD?rats were randomly divided into five groups.One group was sham operation and the other four groups accepted the left anterior descending coronary artery ligation to induce acute MI.After the operation,the sham group and control group were given normal saline and the other three groups were treated with 0.3 mg/kg,1 mg/kg and 3 mg/kg ketanserin respectively.One hour later,the cardiac function was detected by the hemodynamics.Experiment Three: the effect of ketanserin in rat model of heart failure after MI.1.Effects of ketanserin on cardiac function in rats with heart failure after MI.?1?Detection of cardiac function by echocardiography.Male SD rats were anesthetized with ether.Forty rats were subjected to left anterior descending coronary artery ligation and another 6 rats were subjected to sham operation.One week after operation,the 40 rats was detected by echocardiography to eliminated the rats which EF?ejection fraction?was more than 45%.Then the remainders were randomly divided into control and ketanserin treatment groups.Another 6 rats were classified to sham group.Ketanserin group were treated with 1 mg/kg/d ketanserin which was mixed in the feed,while the sham group and control group was given normal diet.Six weeks after operation all animals were subjected to echocardiography to measure the cardiac function.?2?Detection of cardiac function by hemodynamics.The modeling method was same as above.Twent y rats were subjected to left anterior descending coronary artery ligation and another 6 rats were subjected to sham operation.One week after operation,the 20 rats was detected by echocardiography to eliminated the rats whose EF>45%.Then the remainders were randomly divided into control and ketanserin treatment groups and the other 6 rats were classified to sham group.The way of administration was same as above.Six weeks after operation the femoral artery and left ventricular were inserted by catheter to measure hemodynamic indicators.2.Myocardial pathological changes in rats with heart failure after MI treated by ketanserin.Rats were sacrificed by cervical dislocation after the test of hemodynamics in Experiment Two.The hearts were collected for HE and Masson staining.Experiment Four: the therapeutic effect of ketanserin on the rat model of heart failure induced by isoprenaline.1.Effect of ketanserin on cardiac function.Male SD rats were treated with isoprenaline injection and stimulated by ice water to induce heart failure.Twenty-four rats were randomly divided into ketanserin and control groups.The other 6 rats were classified to sham group.Then ketanserin group were treated with 1 mg/kg/d ketanserin which was mixed in the feed,while sham group and control group were given normal diet.Six weeks later all animals were subjected to echocardiography to measure the heart function.2.Effect of ketanserin on cardiac weight index.After echocardiography in Experiment Three,rats were anesthetized and the blood was collected from femoral artery?for the detection of blood biochemical indicators?.Lastly the body weight,whole heart weight,ventricular weight and left ventricular weight were weighed and the heart weight index,ventricular weight index and left ventricular weight index were calculated,respectively.3.Effect of ketanserin on blood biochemical indexes.The blood collected above were centrifuged and the plasma were obtained to measure the level of ANP and Ang?.Experiment Five: effects of ketanserin on long-term survival time of rats with heart failure.The rats of control and ketanserin groups in the echocardiography experiment?Experiment Three?were observed everyday for 400 days to record the death time from the time of administration?one week after operation?.The survival curve was draw by SPSS 21 Kaplan-Meier and the difference between the two groups was compared after the end of the experiment.Results:1.BRS in rats with acute MI was significantly decreased than control but there was no significant change in the blood pressure and heart rate.Compared with ABR-NRs,ABR-DRs were significantly increased in the infarct area ratio and weight ratio after acute MI.2.Ketanserin 0.3 mg/kg,1 mg/kg and 3 mg/kg could improve the BRS in ABR-DR rats.The efficacy of 1 mg/kg and 3 mg/kg was more obvious.All the three doses had no effect on SBP,DBP and HR.In acute MI experiment,ketanserin improved the heart function from 0.3 mg/kg.The efficacy of 1 mg/kg and 3 mg/kg ketanserin were more prominent and there was no obvious difference between these two doses.Comprehensively consider the drug action and safety,we finally selected 1 mg/kg as the follow-up dose.3.The efficacy of ketanserin on heart failure rats after MI.The echocardiographic results showed,the left ventricular end systolic diameter?LVESD?,left ventricular end diastolic diameter?LVEDD?,left ventricular end systolic volume?LVESV?and left ventricular end diastolic volume?LVEDV?in control group were bigger than those in the sham operation group,and the ejection fraction?EF?and fractional shortening?FS?decreased significantly,indicating that this model was successful.Compared with control group,the LVESD,LVEDD,LVESV and LVEDV were significantly lower?P<0.01?,and EF and FS were significantly higher?P<0.05?in ketanserin group,indicating that ketanserin had a beneficial effect on cardiac function in rats with heart failure.Hemodynamic test showed that the left ventricular systolic pressure?LVSP?,the left ventricle maximal rise rate?+dp/dtmax?and the left ventricle maximal decline rate?-dp/dtmin?decreased significantly in the control group compared with the sham group,which showed that the model was successful.Compared with control group,the LVSP,+dp/dtmax and-dp/dtmin in ketanserin group were significantly higher?P<0.05?.There was no different in mean blood pressure?MBP?and heart rate?HR?between ketanserin and control group.HE staining was performed on the heart pathological slices.The cardiomyocytes in sham group were arranged orderly and the morphology was normal.The cardiomyocytes in the control group showed regional irregular muscle cells dissolution and the cells arranged disorderly.Cardiomyocytes in ketanserin group had relatively normal structure and there were only a few cells with structural damage.Compared with the control group,the Masson staining showed there was an obvious reduction of collagen volume fraction in ketanserin group.4.Ketanserin was also effective on heart failure induced by isoprenaline.The echocardiography results were similar to Model One.Ketanserin had a protective effect on heart function in this model.Cardiac weight index showed that the heart weight,heart weight index,ventricular weight index,left ventricular weight and left ventricular weight index in ketanserin group decreased,showed that ketanserin could reduce the cardiac weight index and reverse the myocardial hypertrophy in rats with heart failure.Blood biochemical test showed that compared with control group,ANP and Ang II levels significantly reduced in plasma of ketanserin group,indicating ketanserin can reduce the excessive activation of neuroendocrine system in rats with heart failure.5.The survival time of ketanserin group,which were treated by long-term administration of ketanserin at a dose of 1 mg/kg/d,was significantly longer than control group?P<0.05?.At the end of the observation,41% rats died in ketanserin group and 75% rats died in control group.Conclusion:1.Low ABR function can increase the degree of myocardial infarction in rats.2.Single administration of ketanserin can improve the cardiac function of rats with acute MI.Long-term administration of ketanserin can improve the cardiac function of two different heart failure models and significantly prolong its survival time.3.Ketanserin can alleviate the degree of myocardial collagen fibrosis and reduce the cardiac weight index of heart failure rats.It can also reverse the cardiac hypertrophy and reduce the levels of Ang ?and ANP in plasma.All these effects above may be achieved by improving the ABR function.