| The early stage of pathological cardiac hypertrophy is a compensatory response to adapt to the increase of cardiac load for myocardial tissue.But in the long run,pathological cardiac hypertrophy can lead to the risk of heart failure,arrhythmia,myocardial ischemia,and even sudden death,which is one of the independent risk factors for cardiovascular disease.At present,it is believed that oxidative stress caused by ROS and mitochondrial insufficiency play important roles in the occurrence and development of pathological cardiac hypertrophy.Clinically,calcium channel blocker is one of the classic drugs for the treatment of pathological cardiac hypertrophy.N-n-butyl haloperidol iodide(F2)is a new type of calcium channel blocker developed by our research group.Previous studies have shown that F2 protects myocardium from ischemia-reperfusion injury by blocking L-type Ca2+channel.Further study found that F2 could also improve the hypoxia-reoxygenation injury of cardiomyocytes and cardiac microvascular endothelial cells through inhibiting ROS/JNK signal pathway and mitochondrial oxidative stress.In view of the effects of F2 on intracellular calcium,ROS,and mitochondria,we speculate that F2 may have a new antagonistic effect on pathological cardiac hypertrophy like other calcium channel blockers,or even better than classical calcium channel blockers.Recently,we have demonstrated that F2 could antagonize pathological cardiac hypertrophy through ROS/JNK/Brf1 signal pathway in vitro.However,the effects of F2 on vivo model of cardiac hypertrophy which is more similar to a clinical patient,especially on the structure and function of hypertrophic heart,is not clear.In this study,using the mice models of pathological cardiac hypertrophy induced by transverse aortic constriction(TAC),we investigated whether F2 can improve the abnormal morphology and structure and protect the cardiac function of mice after TAC.On the basis of this,we explored whether the protective effect of F2 is related to its regulation of ROS/JNK/Brfl signal pathway.Methods1.The mouse model of pathological cardiac hypertrophy was established by TAC surgery.After anesthesia and thoracotomy,the ascending aorta was ligated between the origin of the brachiocephalic trunk and the left common carotid artery in mouse.The mouse was fed normally for 4 weeks after surgery.2.Verapamil(Ver)was used as a positive control drug,and the experimental groups were as follows:(1)sham,(2)TAC,(3)TAC+DMSO,(4)TAC+0.125 mg/kg Ver,(5)TAC+0.031 mg/kg F2,(6)TAC+0.062 mg/kg F2,(7)TAC+0.125 mg/kg F2,(8)TAC+0.25 mg/kg F2,(9)TAC+0.50 mg/kg F2.3.Mode and time of administration in mouse:F2 and Ver were administered via tail vein from 1 week to 4 weeks after surgery,respectively.The drug was given for 3 weeks totally.4.Changes of heart weight indexes in mouse,including heart weight/body weight(HW/BW)and heart weight/tibia length(HW/TL),were measured.5.Evaluation of the changes of cardiac function in mouse by small animal ultrasound,including ejection fraction(EF),short axis shortening rate(FS),left ventricular anterior wall thickness at end-systole(LVAWs),left ventricular anterior wall thickness at end-diastole(LVAWd),left ventricular posterior wall thickness at end-systole(LVPWs),left ventricular posterior wall thickness at end-diastole(LVPWd),left ventricular volume at end-systole(LVESV),left ventricular volume at end-diastole(LVEDV),left ventricular inner diameter at end-systole(LVIDs),left ventricular inner diameter at end-diastole(LVIDd).6.The protein expressions of p-JNK,total JNK,Brfl,ANP,and PGC-la were detected by Western Blot.7.Paraffin sections of myocardial tissue were made.The size of cardiac cross section was observed by HE staining.Collagen fiber expression in myocardial tissue was detected by Masson staining.8.Frozen sections of myocardial tissue were made.ROS levels of myocardial tissue were detected by DHE staining.9.The ultrastructure of myocardial tissue was observed by a transmission electron microscope.Results1.Compared with sham group,the protein expression of ANP in TAC group was increased significantly.Five doses of F2 could inhibit the increase of protein ANP induced by TAC in mouse in varying degrees.With the increase of F2 dose,the inhibitory effect on protein ANP increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most obvious inhibitory effect on protein ANP.There was no significant difference in the level of protein ANP between 0.125 mg/kg F2 group and 0.125 mg/kg Ver group.2.Compared with sham group,the heart weight indexes(HW/BW and HW/TL)of mouse in TAC group were significantly higher.Five doses of F2 could inhibit the increases of heart weight indexes induced by TAC in mouse in different degrees.With the increase of F2 dose,the inhibitory effect on heart weight indexes increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most evident inhibitory effects on heart weights.There were no significant differences in the level of heart weight between 0.125 mg/kg F2 group and 0.125 mg/kg Ver group.3.Compared with sham group,the morphology and structure of myocardial tissue in TAC group changed significantly,including heart volume and cardiac cross section were significantly increased,and collagen fibers were significantly proliferated.Five doses of F2 could improve the increases of heart volume and cardiac cross section induced by TAC in mouse,and the middle dose of 0.125 mg/kg F2 group had the best effects among them.Five doses of F2 could also improve the proliferation of collagen fibers induced by TAC in mouse in varying degrees.With the increase of F2 dose,the inhibitory effect on the proliferation of collagen fibers increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most obvious inhibitory effect on collagen fibers.There was no significant difference in the level of collagen fibers between 0.125 mg/kg F2 group and 0.125 mg/kg Ver group.At the same time,compared with sham group,a large number of disordered collagen fibers accumulated were observed by transmission electron microscope in TAC group,which could be significantly improved by given 0.125 mg/kg F2 or 0.125 mg/kg Ver.4.Compared with sham group,EF and FS in TAC group decreased significantly,while LVAWd,LVPWd,LVIDd,LVIDs,LVESV,and LVEDV increased obviously.Five doses of F2 could improve cardiac dysfunction induced by TAC in mouse in varying degrees.With the increase of F2 dose,the promote effect of F2 on EF and FS increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most apparent promote effect on EF and FS.There were no significant differences in the level of EF and FS between 0.125 mg/kg F2 group and 0.125 mg/kg Ver group.With the increase of F2 dose,the inhibitory effect on LVAWd,LVPWd,LVIDd,LVIDs,LVESV,and LVEDV increased at first and then decreased gradually,and the middle dose of 0.125 mg/kg F2 group had the best effect among them.Compared with the same dose of Ver group,the levels of above-mentioned parameters of cardiac function in mouse were not statistically significant.5.Compared with the sham group,TAC promoted the increase of ROS production,the activation of JNK,and the high expression of protein Brfl.Five doses of F2 could inhibit the abnormality of above factors induced by TAC in mouse in different degrees.With the increase of F2 dose,the inhibitory effect on above factors increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most distinct inhibitory effect on above factors.Compared with the same dose of Ver group,the levels of above-mentioned factors in mouse were not statistically significant.6.Compared with sham group,the protein expression of PGC-1α in TAC group was decreased significantly.Five doses of F2 could promote the expression of protein PGC-1α in mouse after TAC in varying degrees.With the increase of F2 dose,the promote effect on the expression of protein PGC-1α increased at first and then decreased gradually.The middle dose of 0.125 mg/kg F2 group had the most obvious promotion effect on protein PGC-1α.There was no significant difference in the level of protein PGC-1α between 0.125 mg/kg F2 group and 0.125 mg/kg Ver group.Meanwhile,compared with sham group,the mitochondrial structure was swollen,vacuolated,even cristae distorted and broken in TAC group,which could be significantly improved by given 0.125 mg/kg F2 or 0.125 mg/kg Ver.Conclusions1.F2 could antagonize the pathological cardiac hypertrophy in mice induced by TAC,and its pharmacological effect showed an inverted "U" dose-effect curve.The pharmacological effect of the best dose group is similar to that of the same dose of Ver group.2.F2 could down-regulate ROS/JNK/Brfl signal pathway and protect mitochondria,which might be an important mechanism for its inhibition of pathological cardiac hypertrophy. |
PDF Full Text Request