Acute heat stress stimulates mitochondrial superoxide production in broiler skeletal muscle, possibly via downregulation of uncoupling protein content
Acute heat stress stimulates mitochondrial superoxide production in broiler skeletal muscle, possibly via downregulation of uncoupling protein content
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DOI：
10.1093/ps/85.7.1259
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发表时间：
2006-07-01
期刊：
影响因子：
4.4
通讯作者：
Toyomizu, M
中科院分区：
文献类型：
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作者：
Mujahid, A;Sato, K;Toyomizu, M
急性热应激(34℃，18h)可导致肉鸡骨骼肌线粒体中ROS水平升高。当电子传输链的需要谷氨酸的复合体I、III和IV或需要琥珀酸的复合体II、III和IV用作底物时，就会发生这种情况。这一结果证实了我们之前的观察结果，即肉鸡在34℃下暴露18h会导致骨骼肌(胸肌)超氧化物歧化产物的增加，并通过证明在热应激期发生底物非依赖性ROS的产生来扩展这一发现。肉鸡暴露于热应激后，骨骼肌中禽解偶联蛋白(AvUCP)的表达水平显著下降，仅为对照组的28%。伴随而来的是avUCP蛋白水平的显著下降，至对照水平的37%。相比之下，热应激对禽腺嘌呤核苷转运体基因表达水平没有影响。这一发现与之前的研究一致，后者表明，在腺嘌呤核苷酸转运体的特异性抑制剂苍术酸羧酸盐的存在下，对照组和热应激鸡的骨骼肌线粒体的超氧化物生成增加是相同的。综上所述，这些结果表明，急性热应激可能通过下调avUCP来刺激肉鸡骨骼肌线粒体超氧化物的产生。本研究首次提供了热应激肉鸡avUCP蛋白合成下调的证据。
Acute heat stress ( 34 C for 18 h) resulted in increased levels of reactive oxygen species (ROS) in mitochondria isolated from the skeletal muscle of broilers. This occurred when glutamate-requiring complexes I, III, and IV of the electron transport chain or succinate-requiring complexes II, III and IV were used as the substrate. This result confirms our previous observation that exposure of broilers to 34 C for 18 h results in increased superoxide production in skeletal ( pectoralis) muscle, and extends this finding by showing that substrate-independent ROS generation occurs during the heat stress period. When broilers were exposed to heat stress, the levels of avian uncoupling protein (avUCP) mRNA in skeletal muscle were significantly decreased, to 28% of the levels found in untreated controls. This was accompanied by a significant decrease in the levels of the avUCP protein, to 37% of control levels. In contrast, avian adenine nucleotide translocator mRNA levels were not affected by exposure to heat stress. This finding is consistent with previous studies which showed that the increases in superoxide production that are observed in the presence of carboxyatractylate, a specific inhibitor of adenine nucleotide translocator, were the same for skeletal muscle mitochondria from both control and heat-stressed chickens. Taken together, these results suggest that acute heat stress stimulates mitochondrial superoxide production in broiler skeletal muscle, possibly via downregulation of avUCP. The present study provides the first evidence that synthesis of avUCP protein is downregulated in heat-stressed broilers.