Reactive Oxygen Species Are Essential for Vasoconstriction upon Cold Exposure.

Di Zhang,Yi Lin,Huimei Shi,Yachun Zheng,Guoqiang Qian,Shiquan Chang,Guoping Zhao,Xin Li,Bei Jing,Zhenni Chen,Yuwei Pan,Francisco J Romero

doi:10.1155/2021/8578452

Abstract

Purpose We explored the role of ROS in cold-induced vasoconstriction and corresponding mechanism. Methods Three experiments were performed. First, we measured blood flow in human hands before and after cold exposure. Second, 24 mice were randomly divided into 3 groups: 8 mice received saline injection, 8 received subcutaneous Tempol injection, and 8 received intrathecal Tempol injection. After 30 min, we determined blood flow in the skin before and after cold exposure. Finally, we used Tempol, CCG-1423, and Go 6983 to pretreat HAVSMCs and HUVECs for 24 h. Then, cells in the corresponding groups were exposed to cold (6 h, 4°C). After cold exposure, the cytoskeleton was stained. Intracellular Ca2+ and ROS levels were measured by flow cytometry and fluorescence microscopy. We measured protein expression via Western blotting. Results In the first experiment, after cold exposure, maximum skin blood flow decreased to 118.4 ± 50.97 flux units. Then, Tempol or normal saline pretreatment did not change skin blood flow. Unlike intrathecal Tempol injection, subcutaneous Tempol injection increased skin blood flow after cold exposure. Finally, cold exposure for 6 h shrank the cells, making them narrower, and increased intracellular Ca2+ and ROS levels in HUVECs and HAVSMCs. Tempol reduced cell shrinkage and decreased intracellular Ca2+ levels. In addition, Tempol decreased intracellular ROS levels. Cold exposure increased RhoA, Rock1, p-MLC-2, ET-1, iNOS, and p-PKC expression and decreased eNOS expression. Tempol or CCG-1423 pretreatment decreased RhoA, Rock1, and p-MLC-2 levels in HAVSMCs. Furthermore, Tempol or Go 6983 pretreatment decreased ET-1, iNOS, and p-PKC expression and increased eNOS expression in HUVECs. Conclusion ROS mediate the vasoconstrictor response within the cold-induced vascular response, and ROS in blood vessel tissues rather than nerve fibers are involved in vasoconstriction via the ROS/RhoA/ROCK1 and ROS/PKC/ET-1 pathways in VSMCs and endothelial cells.

Highlights

With global climate extremes increasing, ambient temperature has become extensively important for various health outcomes and increasingly attracted research attention [1]
The maximum drop in blood flow was 118:4 ± 50:97 flux units at 420 s (Figure 1(c)). These results indicate that cold stimulation reduced skin blood flow
We examined intracellular ROS levels in the different groups of Human VSMCs (HAVSMCs) after cold exposure for 6 h via fluorescence microscopy and flow cytometry (Figure 3(c))

Summary

Introduction

With global climate extremes increasing, ambient temperature has become extensively important for various health outcomes and increasingly attracted research attention [1]. Cold exposure in mammals results in rapid-onset vasoconstriction to protect against heat loss [5]. Oxidative Medicine and Cellular Longevity nonneuromodulatory mechanisms play a critical role in vasoconstriction. ROS played a vital role in vasoconstriction after cold exposure. Pan et al [8] found that increasing endothelial nitric oxide synthase (eNOS) activation and NO release and inhibiting NADPH oxidase-derived ROS generation could improve vascular function, preventing the development and progression of hypertension vasculopathy. It is not clear how ROS regulate vasoconstriction or where ROS exert their effects

Methods

Discussion

Conclusion