Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste, S.C., La Paz, Baja California Sur, 23090, Mexico.
Comp Biochem Physiol A Mol Integr Physiol. 2011 Apr;158(4):438-43. doi: 10.1016/j.cbpa.2010.11.029. Epub 2010 Dec 13.
The diving response in marine mammals results in bradycardia and peripheral vasoconstriction, with blood flow redistributing preferentially to nervous and cardiac tissues. Therefore, some tissues are rendered ischemic during a dive; with the first breath after a dive, blood flow to all tissues is reestablished. In terrestrial mammals, reactive oxygen species (ROS) production increases in response to ischemia/reperfusion and oxidative damage can occur. The capacity of marine mammals to tolerate repeated ischemia/reperfusion cycles associated with diving appears to be due to an enhanced antioxidant system. However, it is not known if diving depth and/or duration elicit differences in tissue capacity to produce ROS and antioxidant defenses in marine mammals. The objective of this study was to analyze ROS production, antioxidant defenses and oxidative damage in marine mammal species that perform shallow/short vs. deep/long dives. We measured production of superoxide radical (O(2)(•-)), oxidative damage to lipids and proteins, activity of antioxidant enzymes, and glutathione levels in tissues from shallow/short divers (Tursiops truncatus) and deep/long divers (Kogia spp.). We found that differences between the diving capacity of dolphins and Kogia spp. are reflected in O(2)(•-) production and antioxidant levels. These differences suggest that shallow/short and deep/long divers have distinct mechanisms to successfully maintain redox balance.
海洋哺乳动物的潜水反应会导致心率减慢和外周血管收缩，血液优先流向神经和心脏组织。因此，在潜水过程中，一些组织会出现缺血；潜水后第一次呼吸时，所有组织的血流都会重新建立。在陆地哺乳动物中，活性氧（ROS）的产生会增加以应对缺血/再灌注，并且可能会发生氧化损伤。海洋哺乳动物能够耐受与潜水相关的反复缺血/再灌注循环的能力似乎归因于增强的抗氧化系统。然而，尚不清楚潜水深度和/或持续时间是否会导致海洋哺乳动物产生 ROS 和抗氧化防御能力的组织差异。本研究的目的是分析在进行浅/短潜水和深/长潜水的海洋哺乳动物物种中 ROS 产生、抗氧化防御和氧化损伤的情况。我们测量了超氧自由基（O(2)(•-))的产生、脂质和蛋白质的氧化损伤、抗氧化酶的活性以及来自浅/短潜水（宽吻海豚）和深/长潜水（海牛科物种）的组织中的谷胱甘肽水平。我们发现，海豚和海牛科物种潜水能力的差异反映在 O(2)(•-)的产生和抗氧化水平上。这些差异表明，浅/短潜水和深/长潜水具有不同的机制来成功维持氧化还原平衡。
