Oyster's cells regulatory volume decrease: A new tool for evaluating the toxicity of low concentration hydrocarbons...

Area of Science:

• Marine Biology
• Environmental Toxicology
• Cellular Physiology

Background:

• Marine ecosystems face risks from hydrocarbon pollution due to fossil fuel activities.
• Early detection of biological impacts from pollutants is crucial for ecosystem health.
• Existing biomarkers may not fully capture the subtle, early effects of chemical exposure.

Purpose of the Study:

• To evaluate a novel cellular biomarker for early quantification of biological risk from hydrocarbon pollutants in seawater.
• To assess the capacity of oyster cells (oocytes and hepatopancreas) to regulate volume under osmotic stress after hydrocarbon exposure.
• To determine the sensitivity and accuracy of the Regulatory Volume Decrease (RVD) process as a biomarker for hydrocarbon contamination.

Main Methods:

• Oocytes and hepatopancreas cells from oysters (Crassostrea gigas) were isolated.
• Cells were subjected to a hypo-osmotic challenge, and volume changes were monitored via imaging over 90 minutes.
• The Regulatory Volume Decrease (RVD) process was analyzed using a first-order exponential decay model to calculate the Recovered Volume Factor (RVF).
• Cells from oysters pre-exposed to diesel oil were compared to control groups.

Main Results:

• Oyster cells exhibited swelling followed by Regulatory Volume Decrease (RVD) in response to hypo-osmotic stress.
• The RVD process, quantified by RVF, was significantly inhibited (approx. 50% decrease) in cells from oysters exposed to diesel oil.
• This inhibition suggests diesel oil altered cell membrane permeability, impacting lipid structure.
• Glutathione S-transferase activity in oyster gills did not increase, indicating RVD's higher sensitivity.

Conclusions:

• The study of the RVD process in sentinel species cells offers a sensitive alternative bioassay for monitoring hydrocarbon pollution.
• This cellular biomarker effectively quantifies early biological risk from pollutants, outperforming established methods.
• The RVD biomarker shows potential for monitoring various environmental chemicals that affect cellular regulation.