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Diving seals, ischemia-reperfusion and oxygen radicals
R Elsner1, S Oyasaeter, R Almaas
1Institute of Marine Science, University of Alaska Fairbanks 99775-7220, USA. elsner@ims.alaska.edu
Summary
Seals possess enhanced cellular protection against diving-induced oxidative stress. Their heart and kidney tissues show greater resistance to ischemia and reperfusion injury compared to pigs.
Area of Science:
- Comparative physiology
- Marine mammal adaptations
- Oxidative stress research
Background:
- Diving mammals like seals tolerate asphyxial hypoxia, leading to ischemia-reperfusion.
- This process can generate harmful reactive oxygen species.
- Seal organs experience varying degrees of ischemia during dives.
Purpose of the Study:
- To compare cardiovascular adaptations and protective mechanisms in seals versus pigs.
- To investigate cellular responses to experimental ischemia in heart and kidney tissues.
- To assess the role of reactive oxygen species in diving physiology.
Main Methods:
- Comparative analysis of ringed seal (Phoca hispida) and domestic pig (Sus scrofa) heart and kidney tissues.
- Experimental induction of ischemia to study tissue reactions.
- Measurement of hypoxanthine production (ATP degradation indicator).
- Assay of superoxide dismutase (SOD) activity (oxygen radical scavenger).
Main Results:
- Seal tissues produced less hypoxanthine than pig tissues, indicating less ATP degradation.
- Superoxide dismutase (SOD) activity was higher in seal heart tissue.
- Unexpectedly higher SOD activity was observed in pig kidney tissue.
Conclusions:
- Seals exhibit enhanced cellular protective mechanisms against reactive oxygen species generated during diving.
- These adaptations help mitigate potential tissue damage from ischemia-reperfusion.
- Comparative studies highlight unique physiological strategies in marine mammals.