OBJECTIVEDiet is an important factor influencing blood pressure and, increases in dietary carbohydrate intake can raise blood pressure in adult rats. A previous study showed that the blood pressure of the rats fed with high-carbohydrate was 5-20 mmHg higher than that of control rats. While the mechanism involved is not clear. This study aimed to investigate the effects of high-sucrose intake on blood pressure of young Wistar rats and the role that sympathetic nerve system in the process.

METHODSMale neonatal Wistar rats were performed sympathectomy operation with 6-hydroxydopamine (6-OHDA) and then divided into four groups: (1) 0.1% VitC saline-common diet group (VN), (2) 0.1% VitC saline-high sucrose (VS), (3) 6-OHDA-common diet group (OHN) and (4) 6-OHDA-high sucrose (OHS) after three week. The data on the body weight (BW), systolic blood pressure (SBP) and heart rate (HR) were recorded. Then the level of blood glucose, serum insulin and angiotensin II (AngII) were measured and the functional studies of the thoracic aorta was performed.

RESULTSThe VS group exhibited higher SBP than the OHS group from the 6th week (113.7 +/- 4.2 mmHg vs. 104.0 +/- 5.8 mmHg, P < 0.01) and the VN group from the 7th week (117.6 +/- 6.3 mmHg vs. 109.6 +/- 4.6 mmHg, P < 0.01), while the SBP of the VN group was similar to those of the OHN group and the OHS group (P > 0.05). No significant differences in blood glucose, serum insulin and insulin sensitive index (ISI) were found among the four groups. The thoracic aorta segments of the VS group had higher contractive response to AngII (P < 0.01) and NE (P < 0.05) than the VN group, but the relaxations to acetylcholine (ACh) and nitroglycerine (NTG) showed no difference among the four groups (P > 0.05).

CONCLUSIONThe high-sucrose diet might elevate the blood pressure in young Wistar rats and the sympathetic system may play an important role in this process.