大麻素 2 型受体激动剂 JWH133 通过减轻脑的延髓头端腹外侧区的炎症降低自发性高血压大鼠的血压。

Cannabinoid type 2 receptor agonist JWH133 decreases blood pressure of spontaneously hypertensive rats through relieving inflammation in the rostral ventrolateral medulla of the brain.

机构信息

Department of Physiology, Hebei Medical University.

Department of Toxicology, Hebei Medical University, Shijiazhuang, China.

出版信息

J Hypertens. 2020 May;38(5):886-895. doi: 10.1097/HJH.0000000000002342.

DOI:10.1097/HJH.0000000000002342

PMID:32238784

Abstract

OBJECTIVE

Neuroinflammation in the rostral ventrolateral medulla (RVLM) has been reported to be associated with hypertension. The upregulation and activation of the cannabinoid type 2 (CB2) receptor may be part of the active process of limiting or downregulating the inflammatory process. This study was designed to determine the role of the CB2 receptor in blood pressure (BP) through relieving neuroinflammation in the RVLM in spontaneously hypertensive rats (SHRs).

METHODS

The long-term effects of intracerebroventricular injection of JWH133, a selective CB2 receptor agonist, on BP, heart rate (HR) and renal sympathetic nerve activity (RSNA) in SHR and Wistar-Kyoto (WKY) rats were determined. ELISA was used to measure the levels of proinflammatory cytokines, and western blotting was employed to detect protein expression of the CB2 receptor. Immunofluorescence staining was used to localize the CB2 receptor. Gene silencing of the CB2 receptor was realized by injecting adeno-associated virus (AAV) expressing CB2-specific shRNA (AAV2-r-CB2shRNA) into the RVLM.

RESULTS

We found that SHRs exhibited higher levels of basal BP, HR, RSNA and proinflammatory cytokines (TNFα, IL-6 and IL-1β) than those in WKY rats. The protein level of the CB2 receptor in the RVLM was robustly increased in SHRs. In addition, the CB2 receptor was mainly expressed on microglia cells of SHRs but not in WKY rats. No expression of the CB2 receptor was found on neurons of either WKY rats or SHRs. Furthermore, intracerebroventricular injection of JWH133 (1 mmol/l, 10 μl) for 28 days decreased the BP, HR, RSNA and proinflammatory cytokines significantly in SHRs, but it had no such effects in WKY rats. These effects were abolished by microinjection of 300 nl AAV2-r-CB2shRNA into the RVLM to knock down the CB2 receptor.

CONCLUSION

Taken together, our results suggest that exciting the CB2 receptor relieves proinflammatory cytokine levels in the RVLM to decrease the BP, HR and RSNA in SHRs.

摘要

目的

已有研究表明延髓头端腹外侧区（RVLM）的神经炎症与高血压有关。大麻素受体 2（CB2）的上调和激活可能是限制或下调炎症过程的主动过程的一部分。本研究旨在通过减轻自发性高血压大鼠（SHR）RVLM 中的神经炎症来确定 CB2 受体在血压（BP）中的作用。

方法

通过向 SHR 和 Wistar-Kyoto（WKY）大鼠的侧脑室注射选择性 CB2 受体激动剂 JWH133，测定其对 BP、心率（HR）和肾交感神经活性（RSNA）的长期影响。酶联免疫吸附试验（ELISA）用于测量促炎细胞因子的水平，蛋白质印迹用于检测 CB2 受体的蛋白表达。免疫荧光染色用于定位 CB2 受体。通过向 RVLM 注射表达 CB2 特异性 shRNA 的腺相关病毒（AAV）来实现 CB2 受体的基因沉默（AAV2-r-CB2shRNA）。

结果

我们发现 SHR 大鼠的基础 BP、HR、RSNA 和促炎细胞因子（TNFα、IL-6 和 IL-1β）水平均高于 WKY 大鼠。RVLM 中的 CB2 受体蛋白水平在 SHR 中显著增加。此外，CB2 受体主要表达于 SHR 的小胶质细胞，而不是 WKY 大鼠。在 WKY 大鼠或 SHR 神经元上均未发现 CB2 受体的表达。此外，侧脑室注射 JWH133（1mmol/l，10μl）28 天可显著降低 SHR 的 BP、HR、RSNA 和促炎细胞因子水平，但对 WKY 大鼠无此作用。将 300nl AAV2-r-CB2shRNA 微注射到 RVLM 以敲低 CB2 受体可消除这些作用。