低压缺氧对大鼠肝脏腺嘌呤核苷酸库、腺嘌呤核苷酸转运体活性及蛋白表达的影响。
Effects of hypobaric hypoxia on adenine nucleotide pools, adenine nucleotide transporter activity and protein expression in rat liver.
作者信息
Li Cong-Yang, Liu Jun-Ze, Wu Li-Ping, Li Bing, Chen Li-Fen
机构信息
Department of Pathophysiology, Institute of High Altitude Military Medicine, Third Military Medical University, Chongqing 400038, China.
出版信息
World J Gastroenterol. 2006 Apr 7;12(13):2120-4. doi: 10.3748/wjg.v12.i13.2120.
AIM
To explore the effect of hypobaric hypoxia on mitochondrial energy metabolism in rat liver.
METHODS
Adult male Wistar rats were exposed to a hypobaric chamber simulating 5,000 m high altitude for 23 h every day for 0 (H0), 1 (H1), 5 (H5), 15 (H15) and 30 d (H30) respectively. Rats were sacrificed by decapitation and liver was removed. Liver mitochondria were isolated by differential centrifugation program. The size of adenine nucleotide pool (ATP, ADP, and AMP) in tissue and mitochondria was separated and measured by high performance liquid chromatography (HPLC). The adenine nucleotide transporter (ANT) activity was determined by isotopic technique. The ANT total protein level was determined by Western blot.
RESULTS
Compared with H0 group, intra-mitochondrial ATP content decreased in all hypoxia groups. However, the H5 group reached the lowest point (70.6%) (P<0.01) when compared to the control group. Intra-mitochondrial ADP and AMP level showed similar change in all hypoxia groups and were significantly lower than that in H0 group. In addition, extra-mitochondrial ATP and ADP content decreased significantly in all hypoxia groups. Furthermore, extra-mitochondrial AMP in groups H5, H15 and H30 was significantly lower than that in H0 group, whereas H1 group had no marked change compared to the control situation. The activity of ANT in hypoxia groups decreased significantly, which was the lowest in H5 group (55.7%) (P<0.01) when compared to H0 group. ANT activity in H30 group was higher than in H15 group, but still lower than that in H0 group. ANT protein level in H5, H15, H30 groups, compared with H0 group decreased significantly, which in H5 group was the lowest, being 27.1% of that in H0 group (P<0.01). ANT protein level in H30 group was higher than in H15 group, but still lower than in H0 group.
CONCLUSION
Hypobaric hypoxia decreases the mitochondrial ATP content in rat liver, while mitochondrial ATP level recovers during long-term hypoxia exposure. The lower level of extra-mitochondrial ATP may be related to the decrease of ANT activity during hypoxia exposure.
目的
探讨低压低氧对大鼠肝脏线粒体能量代谢的影响。
方法
成年雄性Wistar大鼠分别暴露于模拟海拔5000米的低压舱中，每天暴露23小时，持续0（H0）、1（H1）、5（H5）、15（H15）和30天（H30）。通过断头处死大鼠并取出肝脏。采用差速离心法分离肝脏线粒体。用高效液相色谱法（HPLC）分离并测定组织和线粒体中腺嘌呤核苷酸池（ATP、ADP和AMP）的大小。采用同位素技术测定腺嘌呤核苷酸转运体（ANT）活性。通过蛋白质免疫印迹法测定ANT总蛋白水平。
结果
与H0组相比，所有低氧组线粒体ATP含量均降低。然而，与对照组相比，H5组降至最低点（70.6%）（P<0.01）。所有低氧组线粒体ADP和AMP水平变化相似，且显著低于H0组。此外，所有低氧组线粒体外ATP和ADP含量显著降低。此外，H5、H15和H30组线粒体外AMP显著低于H0组，而H1组与对照相比无明显变化。低氧组ANT活性显著降低，与H0组相比，H5组最低（55.7%）（P<0.01）。H30组ANT活性高于H15组，但仍低于H0组。与H0组相比，H5、H15、H30组ANT蛋白水平显著降低，其中H5组最低，为H0组的27.1%（P<0.01）。H30组ANT蛋白水平高于H15组，但仍低于H0组。
结论
低压低氧降低大鼠肝脏线粒体ATP含量，而长期低氧暴露期间线粒体ATP水平有所恢复。低氧暴露期间线粒体外ATP水平降低可能与ANT活性降低有关。
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