Walking promotes metabolic and baroreflex sensitivity improvement in fructose-fed male rats

Abstract

The aim of this study was to investigate metabolic and cardiovascular responses to walking in fructose-fed rats. Male Wistar rats were divided into control (C), sedentary fructose (SF) and walking fructose (WF). Fructose-fed rats received D-fructose (100 g/l). WF rats walked on a treadmill at constant load (0.3 km/h) during 1 h/day, 5 days/week for 8 weeks. Measurements of triglyceride concentrations, adipose tissue and glycemia were carried out together with insulin tolerance test to evaluate metabolic profile. Arterial pressure (AP) signals were directly recorded. Baroreflex sensitivity (BR) was evaluated by the reflex tachycardia (TR) and bradycardia (BR) to AP changes. The results showed that walking decreased the adipose tissue (SF: 6.5 ± 0.4; WF: 2.8 ± 0.1; C: 3.0 ± 0.3 g), blood triglyceride levels (SF: 291 ± 6.5; WF: 150 ± 8.1; C: 103 ± 4.5 mg/dl) and increased insulin sensitivity (SF: 2.5 ± 0.2; WF: 3.3 ± 0.32; C: 4.8 ± 0.4 %/min). Baroreflex sensitivity was improved in the WF group expressed by BR (SF: 0.75 ± 0.10; WF: 1.18 ± 0.10; C: 1.5 ± 0.14 ms/mmHg) and TR (SF: 0.80 ± 0.12; WF: 1.21 ± 0.10; C: 1.35 ± 0.11 ms/mmHg), as well as when verified by the alpha index. Although the WF group showed decreased AP when compared with the SF group, the values still enhanced in relation to C rats (SF: 137 ± 2; WF: 129 ± 1; C: 115 ± 6 mmHg). Our findings allow a better understanding of the effects of walking, a low-intensity exercise training, on the hemodynamic and metabolic aspects of male rats with metabolic syndrome and indicate that walking seems to be particularly effective in treating metabolic disturbances in this model.

Exercise Training Prevents Cardiovascular Derangements Induced by Fructose Overload in Developing Rats

“…The fructose overload induced glucose intolerance and/or insulin resistance, unfavorable changes in lipid profile, as well as an increase in adipose tissue in male and female adults and developing animals [6, 7, 8, 21]. Indeed, our study showed that physical training was able to prevent these metabolic alterations induced by fructose overload as previous reported by others studies [5, 17, 34, 35, 36]. …”

Cardiovascular Changes in Animal Models of Metabolic Syndrome

“…High fructose consumption induces an impairment of baroreflex sensitivity, as evaluated by heart rate responses associated with arterial pressure changes induced by vasoactive drugs [81, 86], as well as by linear regression and alpha-index [84]. Furthermore, unpublished data from our laboratory demonstrated that impairment of baroreflex sensitivity was positively correlated with the number of elastic lamellae in the ascendant aorta.…”

Acute responses of regional vascular conductance to oral ingestion of fructose in healthy young humans

“…Long-term consumption of fructose results in an increase in plasma triglycerides in humans and animals [2-6], and is considered a significant dietary problem in advanced countries associated with obesity and arteriosclerosis [7-9]. Several recent studies have suggested that dietary fructose consumption may lead to the development of cardiovascular diseases such as hypertension [5,8,10,11]. The current understanding to the background of fructose-derived hypertension is unclear as to whether overconsumption of fructose itself induced the elevation of BP directly or indirectly (via hyperuricemia, which is subsequently followed by activation of the rennin-angiotensin-aldosterone system and damage to the renal tubule [11,12]).…”