缺氧对虹鳟肌肉氧化损伤及葡萄糖代谢的影响

Effects of Hypoxia on Oxidative Damage and Glucose Metabolism in Rainbow Trout Muscle

研究缺氧引起的虹鳟肌肉氧化损伤,并从葡萄糖代谢角度探讨其导致抗氧化系统改变的可能机制。随机将虹鳟分为6组,每组9条,其中,对照组(CG,溶解氧(dissolved oxygen,DO)质量浓度(7.5±0.5)mg/L)、中度缺氧组(MHG,DO质量浓度(5.5±0.5)mg/L)、重度缺氧组(SHG,DO质量浓度(3.0±0.5)mg/L)及3个复氧组(DO质量浓度(3.0±0.5)mg/L)在各自DO水平下转运3 h后,复氧组在DO质量浓度(7.5±0.5)mg/L条件下恢复12、24、48 h,检测肌肉中的活性氧水平、抗氧化酶活性、脂代谢相关酶活性、葡萄糖代谢指标和相关基因表达。结果表明:SHG虹鳟肌肉活性氧、丙二醛含量较其他组显著升高(P<0.05),复氧24 h后显著降低(P<0.05),MHG虹鳟肌肉过氧化氢酶活性显著高于CG(P<0.05),MHG和SHG总超氧化物歧化酶和谷胱甘肽过氧化物酶活性显著低于CG(P<0.05);与CG相比,MHG和SHG虹鳟肌肉肌糖原含量、磷酸果糖激酶和丙酮酸激酶活性显著降低(P<0.05),皮质醇含量和己糖激酶活性显著升高(P<0.05);SHG虹鳟肌肉脂肪酶活性与其他组相比显著升高(P<0.05),乳酸含量与CG相比显著升高(P<0.05),MHG虹鳟肌肉脂蛋白脂肪酶活性显著低于CG(P<0.05);缺氧处理后低氧诱导因子1α(hypoxia-inducible factor 1α,HIF-1α)通路的HIF-1α、AMPK、SIRT1和PFK基因mRNA相对表达量显著升高(P<0.05),复氧24 h显著降低(P<0.05)。缺氧可引起虹鳟肌肉氧化损伤,并通过激活HIF-1α通路基因转录调节葡萄糖代谢,抵抗氧化损伤。

This study aims to investigate hypoxia-induced oxidative damage in rainbow trout muscle and to explore the mechanism underlying the resulting alterations in the antioxidant defense system from the perspective of glucose metabolism.Rainbow trout were randomly assigned into six groups with nine fish each:the control group(CG)was transported for 3 h at a dissolved oxygen(DO)level of(7.5±0.5)mg/L;the moderate hypoxia group(MHG)was transported for 3 h at a DO level of(5.5±0.5)mg/L;the severe hypoxia group(SHG)was transported for 3 h at a DO level of(3.0±0.5)mg/L;the three reoxygenated groups were transported for 3 h at a DO level of(3.0±0.5)mg/L and then revived at a DO level of(7.5±0.5)mg/L for 12(R12),24(R24)and 48 h(R48),respectively.We measured reactive oxygen species(ROS)level,antioxidant enzyme activities,lipid metabolism related enzyme activities,glucose metabolism indexes,and related gene expressions in muscle tissues.The results showed that the levels of ROS and malondialdehyde(MDA)in the muscle of rainbow trout significantly increased in the SHG compared to the other groups(P<0.05),and significantly decreased after 24 h of reoxygenation(P<0.05).Catalase(CAT)activity was significantly higher in the MHG than in the CG(P<0.05).Total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px)activities were significantly lower in both MHG and SHG compared to the CG(P<0.05).The MHG and SHG showed a significant decrease in muscle glycogen content as well as phosphofructokinase(PFK)and pyruvate kinase(PK)activities,and a significant increase in cortisol content and hexokinase(HK)activity compared to the CG(P<0.05).The SHG had significantly higher lipase activity than the other groups and significantly higher lactic acid levels than the CG(P<0.05).Lipoprteinlipase activity was significantly lower in the MHG than in the CG(P<0.05).The mRNA relative expression of the HIF-1α,AMPK,SIRT1 and PFK genes in the hypoxia-inducible factor 1α(HIF-1α)signaling pathway was significantly upregulated following hypoxia treatment(P<0.05)but significantly downregulated after reoxygenation for 24 h(P<0.05).Hypoxia-induced oxidative damage in rainbow trout muscle,which is mitigated by the activation of glucose metabolism-related gene transcription in the HIF-1αsignaling pathway.