| Objective:Hypertension, in the annual death rate of about 7 million, is already a hot topic in recent years. Hypertension causes insulin resistance, and insulin resistance to the heart caused by a series of hazards:decreased heart function, disruption of myocardial energy metabolism, mitochondrial functional protein activity disruption. Aerobic exercise can improve insulin resistance in hypertensive rats and enhance heart function. Aerobic exercise promotes mitochondrial biogenesis by enhancing the activation of PGC-1?-NRF1-NRF2 pathway, thus improving cardiac function and endurance levels. Mitochondrial functional protein activity decreased in hypertensive heart. However, there is few studies of myocardium mitochondrial biogenesis of hypertension. This study focus on whether the aerobic exercise could change myocardium mitochondrial biogenesis by PGC-1?-NRF1/NRF2 pathway in self hypertensive rats.Research methods:Subjects for the 4-weeks-old male SHR and WKY rats were 36, divided into four groups:WKY group (WKY, N=7 rats); WKY+exercise group (WKYE, N= 9); SHR group (SHR, N=9); SHR+exercise group (SHRE, N= 11 rats). Swimming adaptive training started the first week. Then started swimming training of 6d/w,120min/d, and the water temperature is 36?.We trained the rats 10 weeks. Cardiac function tested prior to sacrifice (hemodynamic experiments). Then observed myocardial submicroscopic structures, at last tested the key transcription proteins (PGC-1?, NRF1 and NRF2) of mitochondrial biogenesis.The results:1. The aerobic exercise changes the growth of weight in SHR rats. The body weight in SHR is significantly lower than that in WKY. At last week, The body weight in WKYE is significantly lower than that in WKY, and The body weight in SHRE is significantly lower than that in SHR. (WKY vs WKYE:312.9±23.0g vs 273.6±11.8 g, N=16,p<0.05; WKY vs SHR:312.9±23.0g vs 283.92±10.9g, N=18,p<0.05; SHR vs SHRE:283.92±10.9g vs 268.0±19.4g/kg, N=20, p<0.01). This data shows that aerobic exercise reduces the growth of weight in SHR rats.2. The aerobic exercise changes the heart growth in SHR rats.Compared with WKY, the heart coefficient increases significantly in WKYE group(WKY vs WKYE: 3.02±0.23g/kg vs 3.67±0.43 g/kg,n=13,p<0.05)?Compared with WKY,the heart coefficient increases significantly in SHR group(WKY vs SHR:3.0±0.2g/kg vs 3.2±0.1g/kg,n=18,p<0.05)?And compared to the SHR group,heart coefficient significantly increases in SHRE(SHR vs SHRE:3.24±0.12g/kg vsS 3.95±0.31g/kg, n=18,p<0.01).This data shows that aerobic exercise increases the growth of heart in SHR rats.3. After 10 weeks'aerobic exercise,each excersise group's heart function was improved significantly:left ventricular systolic and diastolic function improved, tachycardia has also been improved(LVSP:WKY vs WKYE:62.71±10.70mmHg vs 52.13±8.7mmHg,N=16,p<0.01?WKY vs SHR:62.71±10.70mmHg vs 152± 11.94mmHg,N=16,p<0.01?SHR vs SHRE:152±11.94mmHg vs 117.90± 16.48mmHg,N=20,p<0.01.LVEDP:WKY vs WKYE:20.62±10.71mmHg vs 9.49 ±3.11mmHg,N=16,p<0.01?WKY vs SHR:20.62±10.71mmHg vs 46.73± 12.37mmHg,N=16,p<0.01?SHR vs SHRE:46.73±12.37mmHg vs 14.20± 3.23mmHg,N=20,p<0.01+dp/dtmax:WKY vs WKYE:1182.11±219.47mmHg/s vs 1295.60±254.60mmHg/s,N=16,p<0.01?WKY vs SHR:1182.11± 219.47mmHg/s vs 2484.15±118.39mmHg/s,N=16,p<0.01?SHR vs SHRE: 2484.15±118.39mmHg/s vs2527.84±310.91mmHg/s,N=20,p<0.01.-dp/dtmax: WKY vs WKYE:-854.93±234.81mmHg/s vs-1159.68?234.81mmHg/s,N=16,p <0.01?WKY vs SHR:-854.93±234.81mmHg/s vs-2178.39±193.47mmHg/s,N= 16,p<0.01?SHR vs SHRE:-2178.39±193.47mmHg/s vs-1707.23±669.70mmHg/s, N=20,p<0.01.HR:WKY vs WKYE:345.35±12.20 bpm vs 290.57±14.29 bpm,N= 16,p<0.01?WKY vs SHR:345.35±12.20 bpm vs 370.57±27.14 bpm,N=16,p <0.01?SHR vs SHRE:370.57±27.14 bpm vs 353.55±24.05 bpm,N=20,p<0.01). Tips movement by reducing systolic and diastolic blood pressure,increased systolic and diastolic velocity,and reduced heart rate way to increase stroke volume significantly improved cardiac function WKY rats and SHR rats can significantly improve heart function.4.Aerobic exercise significantly improved cardiac submicroscopic structure SHR rats showed normalization of myocardial mitochondrial morphology,mitochondrial and morphologically normal newborn mitochondria increased significantly. Tip swim improve cardiac structure rats increased mitochondrial biogenesis.5. The aerobic exercise changes the PGC-1?-NRF1-NRF2 pathway. Western Blot test results showed that:Compared with WKY rats, the expressions of myocardial PGC-la, NRF1 and NRF2 increases significantly in WKYE group; Compared with SHR rats, the expressions of myocardial PGC-1?, NRF1 and NRF2 increased significantly in SHRE group.Conclusion:1. Myocardial submicroscopic structural changes as defined by decreased the myocardial mitochondrial number, volume, and abnormal structure, Also heart function and the expressions of myocardial PGC-1?-NRF1/NRF2 decrease in SHR.2. Swimming improves myocardial submicroscopic structural as defined by increased myocardial mitochondrial number, volume, and normal structure, heart function, which attribute to the increased expressions of myocardial PGC-la-NRF1/ NRF2 in SHR. |
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