ABC | Volume 110, Nº3, March 2018

Original Article Lemos et al Exercise improves splenic arterioles In SHR Arq Bras Cardiol. 2018; 110(3):263-269 Figure 1 – Baseline recording of heart rate (1A), systolic arterial pressure (1B), mean arterial pressure (1C) and diastolic arterial pressure (1D) in freely moving rats. WKY S (sedentary normotensive rats); WKY T (trained normotensive rats); SHR S (sedentary hypertensive rats); SHR T (trained hypertensive rats). Bars in figures 1A and 1C represent mean ± SD. Results in figures 1B and 1D are expressed as median (interquartile range). # p < 0.05 vs. WKY S ; *p < 0.001 vs. WKY S ; † p < 0.001 vs. WKY T and ‡ p < 0.001 vs. SHR S . Sedentary Trained (C) 200 250 150 50 0 100 MAP (mmHg) WKY S WKY T SHR S SHR T *† *†‡ (A) 500 400 300 200 100 0 HR (bpm) # *† ‡ (D) 200 250 150 50 100 DAP (mmHg) WKY SHR *† *†‡ (B) 300 200 250 150 100 SAP (mmHg) *†‡ *† Results The SHR S showed higher resting HR in comparison toWKY S (p < 0.001). As expected, both trained groups presented higher resting bradycardia compared with their respective sedentary groups (p < 0.001; Figure 1A). Exercise training also was able to decrease baseline SAP (p < 0.001; Figure 1B), MAP (p < 0.001; Figure 1C) and DAP (p < 0.001; Figure 1D) in hypertensive animals compared with their respective sedentary group. The SHR S presented higher pressure levels than WKY S (p < 0.001) and WKY T (p < 0.001) groups. After the 9-week training period, the AP was similar in WKY T and WKY S . To evaluate the influence of chronic exercise on the tonic autonomic control of the heart, we performed the vagal and sympathetic autonomic blockade with atropine and propranolol injections, respectively, to calculate the vagal (Figure 2A) and sympathetic effects (Figure 2B), as well as the tonic sympathovagal index (Figure 2C) and iHR (Figure 2D). No difference on vagal effect was observed between the hypertensive groups. However, the WKY T group evidenced a higher vagal effect than the WKY S group (p < 0.05). Both hypertensive groups presented a lower vagal effect when compared with their respective normotensive groups (p < 0.001). In addition, no difference in the sympathetic effect was observed between the normotensive groups (p = 0.563). On the other hand, the SHR T group showed a lower sympathetic effect as compared with SHR S group (p = 0.005). Both normotensive groups had a lower sympathetic effect when compared with their respective hypertensive groups (p < 0.001). The sympathovagal index was lower in SHR T than in SHR S (p < 0.05). No difference was observed between the groups regarding iHR. Morphometric analysis after histological processing revealed profound changes in microcirculatory profile of spleen circulation induced by training in hypertensive animals (Table 1). As expected, hypertensive splenic arterioles had a thicker wall than normotensive arterioles (p < 0.001). Despite this, exercise training was effective to normalize SHR arteriole wall/lumen ratio in spleen tissues analyzed when compared with that of SHR S (p < 0.001). The SHR S also presented a greater area of outer wall thickness when compared to WKY S and WKY T (p < 0.001). After exercise training protocol, the SHR T obtained a reduction in the area of the outer wall thickness compared to SHR S (p < 0.001). Similar results were observed in the total area thickness. The SHR S had a higher total area thickness of the splenic arterioles than the normotensive groups (p < 0.005). In addition, the SHR T evidenced an attenuation in total area thickness of splenic arterioles when compared with SHR S (p < 0.005). 265