Study Of The Therapeutic Effect Of Bisoprolol On Animals With Myocardial Hypertrophy Induced By Constriction Of The Abdominal Aorta

With the continuous improvement of living standards,the pet industry in China has become increasingly mature.Companion animals,mainly dogs and cats,have been regarded as important family members,providing important emotional comfort to people.With the continuous improvement of domestic pet diagnosis and treatment levels and animal welfare,domesticated pets have gradually entered the aging stage,and the proportion of cardiovascular and cerebrovascular diseases in clinical cases of pets is gradually increasing.Feline hypertrophic cardiomyopathy is a common heart disease in clinical diagnosis and treatment of cats.Cats with the disease usually do not show obvious clinical symptoms in the early stages,but as the disease progresses,they may experience clinical symptoms such as dyspnea caused by pulmonary edema or sudden hind limb paralysis accompanied by severe pain,and are at risk of sudden death at any time,which poses a challenge to clinical treatment of small animals.Bisoprolol exerts its function mainly by selectively binding to β1-adrenergic receptors,inhibiting the excessive secretion of catecholamines;By inhibiting the basal secretion of renin and stimulating postsecretion,thereby inhibiting mechanisms such as the overactivated RAAS system(Hua et al.2004,Joseph et al 2019),it has the effect of improving coronary blood flow,lowering blood pressure,and reducing myocardial oxygen consumption(Song et al.2016).BIS is commonly used clinically to treat diseases such as hypertension and CHF,and clinical results show that the use of BIS does not increase the risk of cardiovascular and cerebrovascular diseases in patients(Lv and Feng 2019,Yu and Huang 2018).In this experiment established a model of myocardial hypertrophy induced by pressure overload in rats and cats using Abdominal Aortic Constriction method.The effect of Bisoprolol on animal myocardial hypertrophy was observed,and the mechanism of Bisoprolols anti-rat myocardial hypertrophy was explored,in order to provide reference for veterinary clinical medication.The specific methods are as follows:Fifty male Wistar rats weighing about 140 g were randomly divided into 5 groups(n=10):Sham operation(SHAM)group,Model(AAC)group,Bisoprolol(AAC+BIS)group,Chloroquine(AAC+CQ)group,and Bisoprolol + Chloroquine group(AAC+BIS+CQ)group.Each group of rats underwent Abdominal Aortic Constriction surgery(the SHAM group had the abdominal aorta isolated but not constricted)under Isoflurane anesthesia to establish a model of myocardial hypertrophy.After 4 weeks,HE staining,Masson staining,TUNEL staining,Electron microscopy,Echocardiography,Enzyme-linked immunosorbent assay,Immunoblotting,and other detection methods were used to observe the effects of Bisoprolol on the cardiac function and morphological changes of rats,and the expression levels of PINK1/Parkin pathway-related proteins were examined to explore the mechanism of Bisoprolol-mediated regulation of mitochondrial autophagy through the PINK1/Parkin signaling pathway against rat myocardial hypertrophy.Nine 8-month-old British Shorthair cats weighing about 3 kg were randomly divided into3 groups(n=3): sham operation(SHAM)group,model(AAC)group,and Bisoprolol(AAC+BIS)group.After anesthesia with isoflurane,abdominal aortic constriction was performed on each group of cats(the SHAM group had the abdominal aorta isolated but not constricted).After 4 weeks,the levels of myocardial injury biomarkers were measured by Fluorescent quantification,and the effects of Bisoprolol on the cardiac function and structure of cats were observed by Echocardiography.The main research results are as follows:1.Evaluation of the anti-cardiac hypertrophy effect of Bisoprolol in rats(1)Successful establishment of myocardial hypertrophy modelThe blood pressure results four weeks after surgery showed that the blood pressure of rats in the AAC group was significantly increased compared to that of the SHAM group(P<0.05).Compared with the SHAM group,the Left Ventricular Posterior Wall diastolic thickness(LVPWd)of rats in the AAC group was significantly increased(P<0.05),indicating the successful establishment of a rat model of myocardial hypertrophy induced by Abdominal Aortic Constriction(AAC).(2)Effects of Bisoprolol on physiological status and gross anatomy of myocardial hypertrophy ratsCompared with the SHAM group,rats in the AAC group showed depression,rough hair,loose stool,reduced survival rate(P<0.05),slow weight gain(P<0.05),and significantly increased left ventricular weight/body weight ratio(P<0.05).Compared with the AAC group,rats in the AAC+BIS group showed good mental status,shiny hair,normal activity and food intake,normal stool formation,increased survival rate of rats(P<0.05),significant weight gain(P<0.05),and significantly decreased left ventricular weight/body weight ratio(P<0.05).(3)Effects of Bisoprolol on cardiac function and morphological structure of myocardial hypertrophy ratsCompared with the SHAM group,the levels of N-terminal brain natriuretic peptide(NTpro BNP),Creatine kinase isoenzyme(CK-MB),and Lactate dehydrogenase(LDH)in rats in the AAC group were increased(P<0.05),LVPWd and IVSd were significantly increased(P<0.05),and Ejection Fraction(EF)was significantly decreased(P<0.05).Compared with the AAC group,rats in the AAC+BIS group showed decreased levels of NT-pro BNP,CKMB,and LDH(P<0.05),significantly decreased LVPWd and IVSd(P<0.05),and significantly increased EF(P<0.05).(4)Effects of Bisoprolol on the ultrastructure of myocardial cells and mitochondria of myocardial hypertrophy ratsCompared with the SHAM group,myocardial tissue staining in the AAC group showed disordered arrangement of myocardial cells,loose and broken muscle fibers,increased fibrosis level of myocardial interstitium observed by Masson staining,increased apoptosis level of cells observed by TUNEL staining,and disrupted mitochondrial structure,mitochondrial cristae,and broken myofibers observed by transmission electron microscopy.Compared with the AAC group,rats in the AAC+BIS group showed uniform size of myocardial cells,reduced cell swelling,significantly decreased level of myocardial fibrosis,significantly decreased level of cell apoptosis,intact mitochondrial structure,well-arranged myofibers,and more autophagic vacuoles.The myocardial cells of the AAC+CQ group were similar to those of the AAC group,but with increased mitochondrial fragmentation.The myocardial cells of the AAC+BIS+CQ group showed severe mitochondrial swelling,matrix loss,mitochondrial vacuolation.(5)Study on the role of PINK1/Parkin pathway-mediated autophagy in Bisoprolols anti-myocardial hypertrophy effects in ratsCompared with the SHAM group,the expression levels of PINK1,Parkin,Beclin1,and LC3 II,which are related to myocardial autophagy in the hearts of AAC rats,were significantly decreased(P<0.05),while the expression level of P62 protein was significantly increased(P<0.05).Compared with the AAC group,the expression levels of LC3 II,PINK1,Parkin,and Beclin1 proteins in the hearts of AAC+BIS rats were significantly increased(P<0.05),while the expression level of P62 protein was significantly decreased(P<0.05).Compared with the AAC+CQ group,there was no significant difference in the expression levels of various proteins in the hearts of AAC rats;the expression levels of PINK1,Parkin,Beclin1,and LC3 II proteins in the hearts of AAC+BIS+CQ rats were significantly increased(P<0.05),while the expression level of P62 protein was significantly increased(P<0.05).2.Evaluation of the anti-cat hypertrophic cardiomyopathy effect of Bisoprolol(1)Successful establishment of a cat model of myocardial hypertrophyThe results of blood pressure measurement 4 weeks after surgery showed that compared with the SHAM group,the AAC group of cats had a significant increase in blood pressure(P<0.05).Compared with the SHAM group,the AAC group had significant increases in LVPWd,IVSd,and IVSs in rats(P<0.05),indicating the successful establishment of a cat model of myocardial hypertrophy using the abdominal aortic constriction method.(2)Effect of Bisoprolol on the physiological status of hypertrophic cardiomyopathy catsCompared with the SHAM group,the cats in the AAC group were inactive,depressed,had rough hair,decreased appetite,and slow wound healing.Compared with the AAC group,the cats in the AAC+BIS group had a good mental state,shiny hair,and good appetite.(3)Effect of Bisoprolol on the cardiac function and morphological structure of hypertrophic cardiomyopathy catsCompared with the SHAM group,the LVPWd,IVSd,and IVSs of cats in the AAC group were significantly elevated(P<0.05).Compared with the AAC group,the IVSd and IVSs of cats in the AAC+BIS group were significantly reduced(P<0.05).(4)Effect of Bisoprolol on the serum biochemical indicators of hypertrophic cardiomyopathy catsCompared with the SHAM group,the levels of NT-pro BNP and c Tn I in the serum of cats in the AAC group were significantly increased(P<0.05),while the levels of alkaline phosphatase(ALP),alanine aminotransferase(ALT),blood urea nitrogen(BUN),creatinine(CRE),blood glucose(GLU),and total protein(TP)had no significant changes(P>0.05).Compared with the AAC group,the levels of NT-pro BNP and c Tn I in the serum of cats in the AAC+BIS group were significantly decreased(P<0.05),while the levels of ALT,ALP,BUN,CRE,GLU,and TP had no significant changes(P>0.05).In summary,Bisoprolol can improve clinical manifestations,inhibit ventricular remodeling,reduce myocardial fibrosis and apoptosis levels,and reduce damage to heart function and structure in rats with myocardial hypertrophy.Bisoprolol can activate the PINK1/Parkin signaling pathway-mediated mitochondrial autophagy,promote the expression of autophagy-related proteins PINK1,Parkin,LC3 II,and Beclin1,reduce the expression of p62 protein,promote damaged autophagic flux caused by pressure overload,but these effects can be inhibited by autophagy inhibitors.In this study,Bisoprolol improved the utilization of damaged substances within mitochondria,induced the formation of autophagosomes,promoted the smooth flow of autophagy,improved myocardial cell damage,and inhibited myocardial hypertrophy.Bisoprolol can improve the physiological state,heart function,and myocardial morphology and structure of cats with pressure overload-induced myocardial hypertrophy,reduce myocardial damage,and delay the development of myocardial hypertrophy in cats.