Study On The Effect And Mechanism Of Blood Flow Restriction Combined With Low Intensity Resistance Training On The Heart Function Of Spontaneously Hypertensive Rats

Objective: This study aims to explore the effect of blood flow restriction combined with low intensity resistance training on the cardiac function of spontaneously hypertensive rats and its possible mechanism,in order to provide a reliable basis for the future application of this exercise mode instead of high-load resistance training intervention for the treatment of hypertension.Methods: four weeks old male spontaneously hypertensive rats were randomly divided into control group(SHR-SED),low intensity training group(LLRT),pressure training group(BFRT)and high intensity training group(HLRT),15 in each group,a total of 60.In the low intensity training group,35%-55% 1RM progressive low-intensity resistance ladder training was carried out;in the pressure training group,30%-40% blood flow restriction with 35%-55% 1RM progressive low-intensity resistance ladder training was carried out;in the high intensity training group,55%-75% 1RM progressive high-load resistance ladder training was carried out.Bp-2000 was used to detect BP and HR before training,4 weeks after training and 8 weeks after training.High frequency color ultrasound was used to detect heart function before and after training.ELISA was used to detect VEGF,ET-1 and NOS in blood.Western was used The expression of signal protein Pi3kp85,Akt,p-Akt,eNOS,TGF?-1,TGFBR? and TGFBR? in myocardium was detected by blot,the number of new capillaries and muscle fibers in myocardium was detected by HE staining,and the degree of myocardial fibrosis was detected by PSR staining.Results: Physiological index test:(1)compared with SHR-SED,BP and HR of BFRT and LLRT decreased significantly(P<0.05),BP of HLRT increased significantly(P<0.05),BP of BFRT decreased significantly(P<0.05).(2)Compared with SHR-SED,EF and FS of BFRT,LLRT and HLRT increased significantly(P<0.05).Biochemical index test:(1)Compared with SHR-SED,the expression of ET-1 in BFRT and LLRT decreased significantly(P<0.05),VEGF and NOS increased significantly(P<0.05).Compared with the other three groups,the increase of VEGF in HLRT was the highest(P<0.05).(2)Compared with SHR-SED,the expression of Pi3kp85,Akt,p-Akt and eNOS in BFRT myocardium was significantly increased(P<0.05),Akt and eNOS in LLRT myocardium was significantly increased(P<0.05),Akt and p-Akt in HLRT myocardium were significantly increased(P<0.05);compared with LLRT and BFRT,Akt in HLRT myocardium was significantly increased(P<0.05);compared with LLRT,eNOS expression in BFRT myocardium was significantly increased(P<0.05).(3)Compared with SHR-SED,the expression of TGF-?-1 in BFRT and LLRT decreased significantly(P<0.05),while that in HLRT increased significantly(P<0.05).Compared with LLRT,the expression of TGF-?-1 in BFRT decreased significantly(P<0.05);compared with SHR-SED,the expression of TGFBR? in BFRT,LLRT and HLRT increased significantly(P<0.05),and there was no significant difference among the three groups(P > 0.05)Compared with SHR-SED,the expression of TGFBR? in LLRT and HLRT was significantly up-regulated,while that in BFRT was significantly down regulated(P<0.05),and the expression of TGFBR? in LLRT was significantly higher than that in HLRT(P< 0.05).Detection of immunohistochemistry indexes:(1)Compared with SHR-SED,BFRT,LLRT and HLRT showed a significant increase in C / F(the ratio of the number of new capillaries to the number of muscle fibers),but there was no significant difference between LLRT and HLRT.(2)Compared with SHR-SED,the percentage of collagen?/? and CVF% of LLRT and BFRT decreased significantly(P < 0.05),while that of HLRT decreased significantly(P<0.05).Compared with LLRT,the decrease of collagen?/? of BFRT was more significant(P<0.05),while that of HLRT was not significantly different from that of LLRT and BFRT.Conclusion: 1.Low-intensity compressive resistance training activates the Pi3k-akt-eNOS pathway to improve cardiac vascular endothelial function and promote capillary angiogenesis in the myocardium,while low-intensity compressive resistance training affects the expression of TGF?-? and its receptors.Inhibit and reduce myocardial fibrosis,and cooperate with the Pi3k-akt-eNOS pathway to achieve the effect of heart remodeling,improve heart function and lower blood pressure.2.Three kinds of exercise can effectively improve the heart function of SHR without difference,but in the aspect of antihypertensive effect,low-intensity pressor resistance training is the best,low-intensity resistance training alone is the second,high-load resistance training alone has no effect and pressor,so low-intensity pressor resistance training is recommended as the rehabilitation training program for hypertension patients.