不同溶解氧水平对青海湖裸鲤肝组织结构及抗氧化酶活性的影响

Effects of different dissolved oxygen levels on the liver tissue structure and antioxidant enzyme activities of Lake Qinghai Gymnocypris przewalskii

为研究不同溶解氧水平对青海湖裸鲤(Gymnocypris przewalskii)肝组织结构、线粒体超微结构及抗氧化酶活性的影响,选取120尾平均体重为(97.68±0.12)g的青海湖裸鲤,随机分为三组:中度低氧组(3.0±0.1)mg/L、重度低氧组(0.7±0.1)mg/L和常氧组(8.4±0.1)mg/L,于低氧胁迫8 h和24 h,观察肝组织结构并检测线粒体膜电位及抗氧化酶活性。结果显示:中度和重度低氧胁迫使青海湖裸鲤肝血窦扩张,血窦内红细胞数量增多,中度低氧对肝组织显微和线粒体超微结构未造成损伤,线粒体排列整齐,形态正常,但重度低氧使肝细胞出现空泡化,且随低氧胁迫时间延长肝细胞空泡变性更严重,重度低氧24 h时线粒体数量减少,部分线粒体出现空泡化。肝组织线粒体膜电位在中度低氧胁迫后显著升高,重度低氧胁迫后显著降低。中度和重度低氧胁迫使肝组织过氧化氢(H 2O 2)含量、总抗氧化能力(T-AOC)和谷胱甘肽过氧化物酶(GPX)活性显著升高,但对超氧化物歧化酶(SOD)活性无影响;中度低氧对丙二醛(MDA)含量无影响,但重度低氧使MDA含量显著增加。结果表明,低氧胁迫对青海湖裸鲤肝组织造成氧化应激,但中度低氧对肝组织结构和线粒体未造成损伤,重度低氧导致肝组织结构及线粒体损伤,且低氧胁迫后肝组织通过调整相关抗氧化酶活性提高其低氧适应能力。

To study the effects of different dissolved oxygen(DO)levels on the liver microstructure,ultrastructures of mitochondria and antioxidant enzyme activities of the Lake Qinghai Gymnocypris przewalskii,G.przewalskii,with an average weight of(97.68±0.12)g,were randomly divided into three groups based on exposure to the following DO levels:moderate hypoxia(3.0±0.1)mg/L,severe hypoxia(0.7±0.1)mg/L,and normal oxygen level(8.4±0.1)mg/L.After exposure to hypoxia conditions,for 8 h and 24 h,the liver microstructure and ultrastructures of mitochondria were observed and the membrane potential of the mitochondria,the activity of the antioxidant enzymes were determined.The results showed that the blood sinus of liver tissue was expanded and the number of red blood cells of blood sinus were increased under moderate and severe hypoxia.The structure of the liver and the ultrastructure of the mitochondria in the groups under moderate hypoxia were not damaged,the mitochondria were arranged neatly and the morphology was normal.However,the liver tissue showed vacuoles under severe hypoxia,and the vacuoles was aggravated with time expanded of severe hypoxia.The number of mitochondria was decreased and some mitochondria showed vacuolization at 24 h severe hypoxia.The liver mitochondrial membrane potential increased significantly under moderate hypoxia,while the liver mitochondrial membrane potential decreased significantly during severe hypoxia.The content of hydrogen peroxide content(H 2O 2),total antioxidant capacity(T-AOC)and the activities of glutathione peroxidase(GPX)increased under moderate and severe hypoxia,but the activities of SOD remained unchanged under moderate and severe hypoxia.The content of malondialdehyde(MDA)unchanged under moderate hypoxia,but the MDA increased under severe hypoxia.The experiment showed that hypoxia would produce oxidative stress on the liver of G.przewalskii,but the moderate hypoxia stress caused no damage to the liver microstructure and ultrastructures of mitochondria in G.przewalskii,while the severe hypoxia can cause damage to the liver microstructure and ultrastructures of mitochondria.Furthermore,the liver tissue improves the ability of hypoxia adaption by regulating the activity of relevant enzymes after hypoxia.