Relaxin protects astrocytes from hypoxia in vitro

PLoS One. 2014 Mar 5;9(3):e90864. doi: 10.1371/journal.pone.0090864. eCollection 2014.

Abstract

The peptide relaxin has recently been shown to protect brain tissues from the detrimental effects of ischemia. To date, the mechanisms for this remain unclear. In order to investigate the neuroprotective mechanisms by which relaxin may protect the brain, we investigated the possibility that relaxin protects astrocytes from hypoxia or oxygen/glucose deprivation (OGD). Cultured astrocytes were pre-treated with either relaxin-2 or relaxin-3 and exposed to OGD for 24 or 48 hours. Following OGD exposure, viability assays showed that relaxin-treated cells exhibited a higher viability when compared to astrocytes that experienced OGD-alone. Next, to test whether relaxin reduced the production of reactive oxygen species (ROS) astrocytes were exposed to the same conditions as the previous experiment and a commercially available ROS detection kit was used to detect ROS production. Astrocytes that were treated with relaxin-2 and relaxin-3 showed a marked decrease in ROS production when compared to control astrocytes that were exposed only to OGD. Finally, experiments were performed to determine whether or not the mitochondrial membrane potential was affected by relaxin treatment during 24 hour OGD. Mitochondrial membrane potential was higher in astrocytes that were treated with relaxin-2 and relaxin-3 compared to untreated OGD-alone astrocytes. Taken together, these data present novel findings that show relaxin protects astrocytes from ischemic conditions through the reduction of ROS production and the maintenance of mitochondrial membrane potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Astrocytes / cytology*
  • Astrocytes / drug effects*
  • Astrocytes / metabolism
  • Cell Hypoxia / drug effects
  • Cell Survival / drug effects
  • Cytoprotection / drug effects*
  • Glucose / deficiency
  • Membrane Potential, Mitochondrial / drug effects
  • Neuroprotective Agents / pharmacology*
  • Nitric Oxide / metabolism
  • Oxygen
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors / pharmacology
  • Rats
  • Reactive Oxygen Species / metabolism
  • Relaxin / pharmacology*

Substances

  • Neuroprotective Agents
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors
  • Reactive Oxygen Species
  • Nitric Oxide
  • Relaxin
  • Glucose
  • Oxygen

Grants and funding

The authors wish to acknowledge funding from the University of Guelph and NSERC to AJS Summerlee. JM Willcox received salary support from an Ontario Graduate Scholarship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.