Lymphocytes from intermittent hypoxia-exposed rats increase the apoptotic signals in endothelial cells via oxidative and inflammatory injury in vitro.

Abstract

OBJECTIVE:

Obstructive sleep apnea (OSA) has been implicated as a risk factor for atherosclerosis. Intermittent hypoxia (IH) induces oxidative and immuno-inflammatory alterations that could contribute to atherosclerosis. The aim of this study was to examine the effect of lymphocytes from intermittent hypoxia-exposed rats on the apoptotic signals in endothelial cells and the interventional role of tempol.

METHOD:

Male Wistar rats were randomly distributed into three groups (n = 8 each): control group, IH group, and tempol group (exposed to IH and treated with tempol). Lymphocytes isolated from the rats were coincubated subsequently with endothelial cells under normoxia or IH condition. We analyzed endothelial apoptosis-related proteins (Bcl-2, Bax, and caspase-3) by Western blotting and measured the marks of oxidative stress (MDA, SOD, and CAT) and inflammation (TNF-α, IL-8, CRP, and ICAM-1) in cocultural supernatants by ELISA. We also determined endothelial p22(phox), c-fos, and HIF-1α messenger RNA (mRNA) expressions using real time PCR.

RESULTS:

A significant decrease in the Bcl-2 level and the Bcl-2/Bax ratio and a significant increase in Bax and caspase-3 levels in endothelial cells were observed when coincubated normoxically with lymphocytes from IH-exposed rats compared to control (P < 0.01). Moreover, the oxidative stress, inflammation, and mRNA expressions of endothelial p22(phox), c-fos, and HIF-1α were elevated significantly (P < 0.01). The alterations induced by lymphocytes were partially restored by tempol pretreatment while exacerbated by intermittent hypoxic coincubation.

CONCLUSIONS:

Lymphocytes from intermittent hypoxia-exposed rats increased the apoptotic signals in endothelial cells via oxidative and inflammatory injury in vitro, which could be attenuated by tempol.

• Authors: Hengjuan Guo, Jie Cao, Jinna Li, Xiaoyan Yang, Junnan Jiang, Jing Feng, Shuo Li, Jing Zhang, Baoyuan Chen
• Journal: Sleep & breathing = Schlaf & Atmung (Sleep Breath) Vol. 19 Issue 3 Pg. 969-76 (Sep 2015) ISSN: 1522-1709 [Electronic] Germany
• PMID: 25637094 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Apoptosis Regulatory Proteins
• Cyclic N-Oxides
• Hif1a protein, rat
• Hypoxia-Inducible Factor 1, alpha Subunit
• Inflammation Mediators
• Proto-Oncogene Proteins c-bcl-2
• Proto-Oncogene Proteins c-fos
• Spin Labels
• NADPH Oxidases
• Cyba protein, rat
• tempol

Topics

• Animals
• Apoptosis (drug effects, physiology)
• Apoptosis Regulatory Proteins (metabolism)
• Cyclic N-Oxides (pharmacology)
• Endothelial Cells (drug effects, physiology)
• Hypoxia (physiopathology)
• Hypoxia-Inducible Factor 1, alpha Subunit (metabolism)
• In Vitro Techniques
• Inflammation Mediators (metabolism)
• Male
• NADPH Oxidases (metabolism)
• Oxidative Stress (drug effects, physiology)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• Proto-Oncogene Proteins c-fos (metabolism)
• Rats
• Rats, Wistar
• Spin Labels