| Objective To establish rat heart failure model by using modified method of partial coarctation in abdominal aorta and to observe the effects of β3-adrenoceptor on cardiac function and cardiac energy metabolism in heart failure by using β3-adrenoceptor agonist and inhibitor on those model rats.And to explore the possible mechanisms of energy metabolism mediated by Beta 3-AR in myocardial remodeling of heart failure rats. Methods 1) Healthy male wistar rats were randomly divided into five groups: 1)Normal control group(n=15): Rats were Fed conventionally and with no special treatment; 2)Surgery group(CHF grooup,n=30): Rats Received a surgery of partial coarctation in the abdominal aorta by improved method and received a-four-weeks intraperitoneal injection of saline from the eight week after surgery(saline, 1ml/kg, intravenous injection,two times a week, 4 weeks); 3) sham-operation group(n=15): without ligation in abdominal aorta, while other operation process were the same with the surgery group and and with no special treatment;4)β3-adrenoceptor agonist group(BRL group,n=30):Rats received a same surgery with the Surgery group and received a-four-weeks intravenous injection of β3-adrenoceptor agonist BRL37344 from the eight week after surgery(BRL37344,4nmol/kg,intravenous injection,two times a week,4 weeks);5)β3-adrenoceptor inhibitor group(SR group,n=30):Rats received a same surgery with the Surgery group and received a-four-weeks intraperitoneal injection of β3-adrenoceptor inhibitor SR59230 A from the eight week after surgery(SR59230A,85nmol/kg,intraperitoneal injection,two times a week for 4 weeks).Related indicators were detected at the end of the intervention and 4 weeks after the intervention. 2) Hemodynamics and cardiac function of all the rats were calculated by using Lef-heart-catheterization and Echocardiography 3) To observe myocardial morphological changes of all the rats with HE staining and to observe the expression and localization of beta3-AR, PPARα, ERK2, AMPKα2, UCP2 protein in all groups by using immuno-histochemistry. 4) The contents of FFA, glucose, lactic acid, acetone and the activity of ATP enzyme in all groups were detected by kits. 5) Expression of beta3-AR, PPARα, ERK2, AMPKα2, UCP2 m RNA was measured by RT-PCR.; 6) Expression of beta3-AR, PPARα protein was detected by Western Blotting. Results 1) Cardiac function:Compared with normal control group, all indicators of sham group almost have no changes. After 12 weeks of surgery,LVIDD, LVIDS, IVSD, IVSS of heart failure group,BRL group and SR group were increased, while FS, EF was lower, compared with normal group(P <0.05);compared with the heart failure group, IVSS, IVSD of SR group were not statistically significant, while LVIDD, LVIDS,FS, EF were statistically significant(P <0.05), and all indicators of BRL group were statistically significant(P <0.05). After 16 weeks of surgery, all indicators of sham group have no significant difference compared with normal control group.LVIDD, LVIDS, IVSD, IVSS of heart failure group,BRL group and SR group were increased,FS, EF were lower, compared with normal group(P <0.05).IVSS of SR group was still not statistically significant compared with herat failure group.All indicators of BRL group were statistically significant compared with herat failure group(P <0.05). 2) Hemodynamics:Compared with normal control group, all indexes of sham group were not statistically significant.After12 weeks of surgery,HR、LVSP、±dp/dtmax of heart failure group,BRL group and SR group were decreased, LVEDP was higher, compared with normal group(P <0.05).Compared with heart failure group,-dp/dtmax,LVEDP of SR group were statistically significant, while HR、LVSP、±dp/dtmax were not significantly changed(P <0.05),except HR,all indicators BRL group were statistically significant(P <0.05). After 16 weeks of surgery, all indicators of sham group have no significant difference compared with normal control group.LVSP、±dp/dtmax、LVEDP of BRL group and SR group were statistically significant compared with heart failure group(P <0.05). 3) HE staining: Sham group had no significant change with normal control group.Myocardial celldegeneration, atrophy, focal necrosis,myocardial fibers loosely arranged, disorders,myofibril fracturing,inflammatory cells were finded in heart failure group and BRL group. BRL group is more obvious, while SR group changes lighter than the heart failure group. immuno-histochemistry:β3-AR, PPARα, ERK2, AMPKα2, UCP2 protein expression levels were no significant difference between normal group and the sham group. β3-AR, ERK2, UCP2 protein expression levels of Heart failure group and BRL group was increased than normal control group, the increase is more significant in BRL group, while PPARα, AMPKα2 expression levels were lower than normal group, BRL group reduced more obvious. β3-AR, ERK2, UCP2 expression levels of SR group were lower than the heart failure group,while increased compared with the normal group, PPARα, AMPKα2 expression levels of SR group were higher than heart failure group, but lower than normal group.Changes above were more evident in 16-weeks group. 4) Myocardial FFA, glucose, lactic acid, acetone content and ATP activity:Myocardial contens of free fatty acids, glucose, lactate, pyruvate,ATP enzyme activity were had no significant differences compared with the normal group(P> 0.05).Myocardial FFA, lactic acid, pyruvic acid contents of heart failure group and BRL group were significantly higher than those in the normal group(P <0.05 or P <0.01).,but glucose content, Na+K+-ATPase, Ca2+Mg2+-ATPase were lower than those in the normal group,the difference was statistically significant(P <0.05 or P <0.01).Contents of free fatty acids, lactic acid, pyruvic acid of SR group were lower than HF group, Na+K+-ATPase, Ca2+Mg2+-ATPase activity were increased compared with HF group. 5) RT-PCR results:β3-AR, PPARα, AMPKα2, UCP2, ERK2 m RNA expression levels were had nosignificant difference between normal group and the sham group(P> 0.05). β3-AR, PPARα, AMPKα2 m RNA expression levels of CHF group, BRL group and SR group were significantly higher than normal(P <0.05),and the 16-weeks group was significantly more than the 12-weeks group(P <0.05). PPARα, AMPKα2 m RNA expression levels of CHF group, BRL group were lower than normal group(P <0.05), 16-weeks group was more obvious(P <0.05). β3-AR,UCP2, ERK2 m RNA expression levels of CHF group and BRL group were significantly lower than normal(P <0.05).β3-AR,UCP2, ERK2 m RNA expression levels of BRL group were incresed compared with CHF group and SR group(P <0.05),but PPARα, AMPKα2 m RNA expression levels were lower. 6) Western Blotting Results: Myocardial β3-AR, PPARα protein contents were had no significant difference between normal group and the sham group(P> 0.05).β3-AR protein expression levels of CHF group, BRL group, SR group(2.01 ± 0.01,2.35 ± 0.06,1.96 ± 0.03) were significantly higher than the normal group(P <0.05); and the 16-weeks group was significantly more than the 12-weeks group(P <0.05).β3-AR protein expression level of BRL group was more than the HF group(P <0.05). PPARα protein expression level of BRL group was lower than the HF group(P <0.05).PPARα protein expression of SR group was higher than BRL group and heart failure group,but expression level of β3-AR protein was lower. Conclusions 1) After excited,β3-AR can exacerbate Cardiac function and increase energy metabolism reconstruction in heart failure rats; 2) β3-AR may mediate remodeling of energy metabolism by regulating PPARα, AMPKα2, UCP2, ERK2 expression in rats with heart failure. |
PDF Full Text Request