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CJAP ›› 2016, Vol. 32 ›› Issue (6): 481-486.doi: 10.13459/j.cnki.cjap.2016.06.001

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Iptakalim ameliorates relaxation to acetylcholine in thoracic aortic rings impaired by microvesicles derived from hypoxia/reoxygenation-treated HUVECs

Kun-wei ZHANG, Shao-xun WANG, Ye-yi LI, Su WEI, Man SHANG, Chao LIU, Miao LIU, Yi-lu WANG, Qian ZHU, Yan-na WU, Jun-qiu SONG, Yan-xia LIU   

  1. Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
  • Received:2016-11-09 Revised:2016-11-21 Online:2016-11-28 Published:2018-06-19

Abstract: Objective: To investigate the effect of Iptakalim (Ipt) preventing injury of endothelial microvesicles (EMVs) derived from hypoxia/reoxygenation (H/R)-treated HUVECs on the relaxation of rat thoracic aortic rings and explore the underlying mechanism. Methods: H/R injury model was established to release H/R-EMVs from HUVECs. H/R-EMVs from HUVECs were isolated by ultracentrifugation from the conditioned culture medium. H/R-EMVs were characterized by using Transmission Electron Microscope (TEM). Thoracic aortic rings of rats were incubated with 10-7-10-3 mol/L Ipt and co-cultured with 10 μg/ml H/R-EMVs for 4 hours, and their endothelium-dependent relaxation in response to acetylcholine (ACh) was recorded in vitro. The nitric oxide (NO) production of ACh-treated rat thoracic aortic rings was measured by using Griess reagent. The expression of endothelial NO synthase (eNOS), phosphorylated eNOS (p-eNOS, Ser-1177), serine/threonine kinas (Akt) and phosphorylated Akt (p-Akt, Ser-473) in the thoracic aortic rings of rats was detected by Western blotting. Results: H/R-EMVs were induced by H/R-treated HUVECs and isolated by ultracentrifugation. The isolated H/R-EMVs subjected to TEM revealed small, rounded vesicles (100-1 000 nm) surrounded by a membrane. H/R-EMVs impaired relaxation induced by ACh of rat thoracic aortic rings significantly. Compared with H/R-EMVs treatment individually, relaxation and NO production of rat thoracic aortic rings were increased by Ipt treatment in a concentration-dependent manner (P<0.05, P<0.01). The expression of total eNOS (t-eNOS) and total Akt (t-Akt) was not affected by Ipt or H/R-EMVs. However, the expression of p-eNOS and p-Akt increased after treated with Ipt (P<0.01). Conclusion: Based on H/R-EMVs treatment, ACh induced endothelium-dependent relaxation of rat thoracic aortic rings was ameliorated by Ipt in a concentration-dependent manner. The mechanisms involved the increase in NO production, p-eNOS and p-Akt expression.

Key words: Iptakalim, hypoxia/reoxygenation, endothelial microvesicles, rat aortic rings, NO, eNOS, Akt

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