Antioxidant therapy reverses sympathetic dysfunction, oxidative stress, and hypertension in male hyperadipose rats

The rostral ventrolateral medulla (RVLM) is the main sympathetic output of the central nervous system to control blood pressure. Reportedly, reactive oxygen species (ROS) can increase arterial pressure, leading to hypertension. As ROS increase the sympathetic tone in RVLM and obese animals present grater oxidative stress, it would be important to note this relationship.

Therefore, we evaluated the systemic and central effects (in the RVLM) of vitamin C (vit C, an antioxidant) on the redox balance and cardiovascular and autonomic profiles in hyperadipose male rats. We also evaluated the neurotransmission by L-glutamate (L-glu) and vit C in the RVLM of awake hyperadipose rats.

Our study confirmed that hyperadipose rats were hypertensive and tachycardic, presented increased sympathetic and decreased parasympathetic modulation of the heart, and had increased plasma lipoperoxidation compared with the control rats (CTR). Oral vitamin C treatment reverted cardiovascular, autonomic, and plasma redox dysfunction. Hyperadipose rats presented a higher blood pressure increase after L-glu microinjection and a lower response to vit C in the RVLM compared with the CTR group. Biochemical analysis of redox balance in RVLM punches showed that hyperadipose rats have increased NBT and T-BARS, and after treatment with vit C, the oxidative profile decreased. The antioxidative activity of vit C reduced the amount of ROS in the RVLM area that might have resulted in lowered blood pressure and sympathetic modulation.

Our data suggest central and peripheral benefits of vit C treatment on cardiovascular, autonomic, and oxidative dysfunctions in hyperadipose animals.