Chronic infusion of epigallocatechin-3-O-gallate into the hypothalamic paraventricular nucleus attenuates hypertension and sympathoexcitation by restoring neurotransmitters and cytokines. (16th November 2016)

• Record Type: Journal Article
• Authors: Yi, Qiu-Yue; Li, Hong-Bao; Qi, Jie; Yu, Xiao-Jing; Huo, Chan-Juan; Li, Xiang; Bai, Juan; Gao, Hong-Li; Kou, Bo; Liu, Kai-Li; Zhang, Dong-Dong; Chen, Wen-Sheng; Cui, Wei; Zhu, Guo-Qing; Shi, Xiao-Lian; Kang, Yu-Ming
• Is Part Of: Toxicology letters. Volume 262(2016)
• Page Start: 105
• Page End: 113
• Publication Date: 2016-11-16
• Subjects: Epigallocatechin-3-O-gallate -- Paraventricular nucleus -- Oxidative stress -- Cytokines -- Neurotransmitters -- Hypertension; Toxicology -- Periodicals; 363.179
• DOI: 10.1016/j.toxlet.2016.09.010
• Languages: English
• ISSNs: 0378-4274

Abstract

Highlights: PVN infusion of EGCG in spontaneously hypertensive rats is reported. PVN infusion of EGCG attenuates hypertension and sympathoexcitation. PVN infusion of EGCG attenuates PVN oxidative stress and NF-κB activity. PVN infusion of EGCG restores hypertension-induced imbalance of cytokines. PVN infusion of EGCG restores hypertension-induced imbalance of neurotransmitters. Abstract: Reactive oxygen species (ROS) in the brain are involved in the pathogenesis of hypertension. Epigallocatechin-3- O -gallate (EGCG), one of the active compounds in green tea, has anti-oxidant, anti-inflammatory and vascular protective properties. This study was designed to determine whether chronic infusion of EGCG into the hypothalamic paraventricular nucleus (PVN) attenuates ROS and sympathetic activity and delays the progression of hypertension by up-regulating anti-inflammatory cytokines, reducing pro-inflammatory cytokines (PICs) and decreasing nuclear factor-kappa B (NF-κB) activity, as well as restoring the neurotransmitters balance in the PVN of spontaneously hypertensive rats (SHR). Adult normotensive Wistar–Kyoto (WKY) rats and SHR received bilateral PVN infusion of EGCG (20 μg/h) or vehicle via osmotic minipumps for 4 weeks. SHR showed higher mean arterial pressure, plasma proinflammatory cytokines and circulating norepinephrine (NE) levels compared with WKY rats. SHR also had higher PVN levels of the subunit of NAD(P)H oxidase (gp91 phox ), ROS, tyrosine hydroxylase, and PICs; increased NF-κB activity; and lower PVN levels of interleukin-10 (IL-10) and 67 kDa isoform of glutamate decarboxylase (GAD67) than WKY rats. PVN infusion of EGCG attenuated all these changes in SHR. These findings suggest that SHR have an imbalance between excitatory and inhibitory neurotransmitters, as well as an imbalance between pro- and anti-inflammatory cytokines in the PVN. Chronic inhibition of ROS in the PVN restores the balance of neurotransmitters and cytokines in the PVN, thereby attenuating hypertensive response and sympathetic activity.