Microcystin-LR induced reactive oxygen species mediate cytoskeletal disruption and apoptosis of hepatocytes in Cyprinus carpio L

PLoS One. 2013 Dec 20;8(12):e84768. doi: 10.1371/journal.pone.0084768. eCollection 2013.

Abstract

Microcystins (MCs) are a group of cyclic hepatotoxic peptides produced by cyanobacteria. Microcystin-LR (MC-LR) contains Leucine (L) and Arginine (R) in the variable positions, and is one of the most common and potently toxic peptides. MC-LR can inhibit protein phosphatase type 1 and type 2A (PP1 and PP2A) activities and induce excessive production of reactive oxygen species (ROS). The underlying mechanism of the inhibition of PP1 and PP2A has been extensively studied. The over-production of ROS is considered to be another main mechanism behind MC-LR toxicity; however, the detailed toxicological mechanism involved in over-production of ROS in carp (Cyprinus carpio L.) remains largely unclear. In our present study, the hydroxyl radical (•OH) was significantly induced in the liver of carp after a relatively short-term exposure to MC-LR. The elevated reactive oxygen species (ROS) production may play an important role in the disruption of microtubule structure. Pre-injection of the antioxidant N-acetyl-cysteine (NAC) provided significant protection to the cytoskeleton, however buthionine sulfoximine (BSO) exacerbated cytoskeletal destruction. In addition, the elevated ROS formation induced the expression of apoptosis-related genes, including p38, JNKa, and bcl-2. A significant increase in apoptotic cells was observed at 12-48 hours. Our study further supports evidence that ROS are involved in MC-LR induced damage to liver cells in carp, and indicates the need for further study of the molecular mechanisms behind MC-LR toxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Buthionine Sulfoximine / toxicity
  • Carps / metabolism*
  • Carps / physiology
  • Cytoskeleton / drug effects
  • Cytoskeleton / pathology*
  • DNA Primers / genetics
  • Flow Cytometry
  • Hepatocytes / metabolism*
  • Hepatocytes / physiology
  • Immunohistochemistry
  • Marine Toxins
  • Microcystins / metabolism
  • Microcystins / toxicity*
  • Microscopy, Confocal
  • Reactive Oxygen Species / metabolism*
  • Real-Time Polymerase Chain Reaction
  • Time Factors

Substances

  • DNA Primers
  • Marine Toxins
  • Microcystins
  • Reactive Oxygen Species
  • Buthionine Sulfoximine
  • cyanoginosin LR

Grants and funding

This research was supported by the National Key Technology R&D Program (Grant number 2011BAE06B09-5) and the National Environmental Protection Public Welfare Science and Technology Research Program of China (Grant number 201009033). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.