Objective To observe the pathological changes of heart failure model in rats and investigate the protective effects of Long Nao secondary glycosides(LN)on a rat model of heart failure.Study the synergism action of LN in Shen Mai injection(SM).Explore the intervention mechanism about LN from PI3K/CaMKⅡ pathway,which can support experimental basis for LN in Shen Mai injection application.Methods(1)40 male SD rats,weighing 220~250g,were taken.32 of them were operated the transverse aortic constriction(TAC).The same operation was performed on another 8 rats,except for the ligation of the transverse aorta.Echocardiographic assessment,hemodynamics measurement,serum NT-proBNP,HsCRP,AngⅡ and NO measurement were performed to model group at 4 weeks,8 weeks,12 weeks after the operation.HE and Masson staining were used to observe the pathological changes of myocardial tissue.RT-PCR were used for detecting the mRNA expression of ICAM、eNOS、TGF-β.(2)100 male SD rats,weighing 220-250g,were also taken 92 of them were operated the TAC.The same operation was performed on another 8 rats,except for the ligation of the transverse aorta.After the TAC,the surviving rats were divided into 7 groups according to the modeling time,namely model group(Model,5%GS 3mL/kg),low-dose LN group(LN-L,LN 0.2mg/kg),high-dose LN group(LN-H,LN 5mg/kg),low-dose SL group(SL-L,Shen Mai injection containing 0.15mg/kg LN),high-dose SL group(SL-H,Shen Mai injection containing 0.3mg/kg LN),SM group(SM,SM 3mL/kg),captopril group(CAP,CAP 12.5 mg/kg).The rats were given corresponding drugs respectively,once per day,for 4 weeks.Echocardiographic assessment,hemodynamics measurement,serum NT-proBNP,HsCRP,AngⅡ and NO measurement were performed to the sham group and administration group after 4 weeks.Killed the Rats and toke the myocardium by HE and Masson staining to observe the pathological changes.RT-PCR were used for detecting the mRNA expression of PI3K,AKT、CaMK Ⅱ.And western blot were used to test PI3K,p-AKT,AKT,CaMK Ⅱ protein expression.Results(1)Compared to sham operated group,the content of serum Ang Ⅱ、hsCRP were increased after TAC.The content of serum NT-proBNP,NO were increased first and then decrease and peaked at 8 weeks after TAC(P<0.05).±dp/dtmax were reduced significantly(P<0.05).Pathological observation showed that myocardial hypertrophy,inflammatory cell infiltration at 4 weeks after TAC,myocardial connective tissue hyperplasia,cytoplasm significantly increasing,myocardial blood vessel wall thickening at 8 weeks after TAC,collagen deposition,myocardial fibrosis at 12 weeks after TAC.ICAM mRNA expression was notably increased at 4 weeks after TAC(P<0.05),and showed a downward trend at 8 weeks after TAC(P>0.05).eNOS mRNA expression was obviously increased at 4 weeks and 8 weeks after TAC.TGFβ mRNA expression was remarkably increased after TAC.(2)Compared to the sham operation group,myocardial tissue showed myocardial hypertrophy,collagen fiber deposition.EF,FS,±dp/dtmax reduced significantly,serum hsCRP,NT-proBNP,Ang Ⅱ increased significantly,the mRNA and protein expression of PI3K,Akt(p-AKT),CaMK Ⅱ in myocardial tissue were all notably increased(P<0.05).Compared to the model group,the administration group of myocardial hypertrophy was significantly alleviated,collagen fibre deposition reduced.EF,FS,±dp/dtmax of SL-H group were increased remarkably(P<0.05),which can improve cardiac function and hemodynamics parameters.The content of NT-proBNP and Ang Ⅱ in serum were significantly reduced(P<0.05)and the content of hsCRP in serum were notably reduced in SL-L group,SL-H group and CAP group.The mRNA and protein expression of PI3K,AKT(p-AKT),CaMK Ⅱ displayed a downward trend,while the SL-L and SL-H group were significantly decreased(P<0.05).Conclusions(1)Transverse aortic constriction induces heart failure in rats.The pathological processes are compensatory hypertrophy at 4 weeks after operation,initial reaction of decompensation at 8 weeks after the operation,and heart failure at 12 weeks after operation.(2)LN and SL can remarkably reduce the level of NT-proBNP、Ang Ⅱ and hsCRP in serum,±dp/dtmax、EF and FS,thereby improving cardiac structure and function,indicating that LN has a protective effect on myocardial in HF rats.The mechanism may be related to inhibit cardiac hypertrophy,inflammation,improve heart function,and inhibit the related protein activation of PBK/CaMKⅡ pathway.In addition,the combination of LN and SM has the effect of enhancing the efficacy of SM. |