Souza Silvia B C, Flues Karin, Paulini Janaina, Mostarda Cristiano, Rodrigues Bruno, Souza Leandro E, Irigoyen Maria-Cláudia, De Angelis Kátia
Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
Hypertension. 2007 Oct;50(4):786-91. doi: 10.1161/HYPERTENSIONAHA.107.095000. Epub 2007 Jul 30.
Diabetes and menopause markedly increase the risk of cardiovascular disease in women. The objective of the present study was to investigate the effects of exercise training on cardiovascular autonomic dysfunction and on total mortality in diabetic female rats undergoing ovarian hormone deprivation. Female Wistar rats were divided into ovariectomized groups: sedentary and trained controls and sedentary and trained diabetic rats (streptozotocin, 50 mg/kg IV). Trained groups were submitted to an exercise training protocol on a treadmill (8 weeks). The baroreflex sensitivity was evaluated by heart rate responses to arterial pressure changes. Heart rate variability was determined using the SD of the basal heart rate. Vagal and sympathetic tonus were evaluated by pharmacological blockade. Diabetes impaired baroreflex sensitivity ( approximately 55%), vagal tonus ( approximately 68%), and heart rate variability ( approximately 38%). Exercise training improved baroreflex sensitivity and heart rate variability in control and diabetic groups in relation to their sedentary groups. Trained control rats presented increased vagal tonus compared with that of sedentary ones. The sympathetic tonus was reduced in the trained diabetic group as compared with that of other studied groups. Significant correlations were obtained between heart rate variability and vagal tonus with baroreflex sensitivity. Mortality, assessed during the training period, was reduced in trained diabetic (25%) rats compared with mortality in sedentary diabetic rats (60%). Together, these findings suggest that decreases in baroreflex sensitivity and heart rate variability may be related to increased mortality in female diabetic subjects and that improved autonomic regulation induced by exercise training may contribute to decreased mortality in this population.
糖尿病和更年期会显著增加女性患心血管疾病的风险。本研究的目的是调查运动训练对接受卵巢激素剥夺的糖尿病雌性大鼠心血管自主神经功能障碍和总死亡率的影响。将雌性Wistar大鼠分为去卵巢组：久坐对照组和训练对照组，以及久坐糖尿病组和训练糖尿病组（链脲佐菌素，50 mg/kg静脉注射）。训练组在跑步机上进行运动训练方案（8周）。通过心率对动脉压变化的反应评估压力反射敏感性。使用基础心率的标准差确定心率变异性。通过药理学阻断评估迷走神经和交感神经张力。糖尿病损害了压力反射敏感性（约55%）、迷走神经张力（约68%）和心率变异性（约38%）。与久坐组相比，运动训练改善了对照组和糖尿病组的压力反射敏感性和心率变异性。训练后的对照大鼠与久坐大鼠相比，迷走神经张力增加。与其他研究组相比，训练后的糖尿病组交感神经张力降低。心率变异性和迷走神经张力与压力反射敏感性之间存在显著相关性。在训练期间评估的死亡率方面，训练后的糖尿病大鼠（25%）与久坐糖尿病大鼠（60%）相比有所降低。总之，这些发现表明，压力反射敏感性和心率变异性的降低可能与女性糖尿病患者死亡率增加有关，而运动训练诱导的自主神经调节改善可能有助于降低该人群的死亡率。
