Amcoff P, Åkerman G, Börjeson H, Tjärnlund U, Norrgren L, Balk L
Department of Pathology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, PO Box 7028, S-750 07, Uppsala, Sweden
Aquat Toxicol. 2000 Apr 1;48(4):391-402. doi: 10.1016/s0166-445x(00)00089-8.
Sea-run Baltic salmon (Salmo salar) populations have been affected by the M74 syndrome since 1974 causing high yolk-sac fry losses in Swedish compensatory rearing plants. M74 has been shown to be a maternally transmitted thiamine (vitamin B(1)) deficiency. The aim of this study was to investigate possible relationships between thiamine and hepatic activities of the thiamine-dependent enzymes transketolase (TK) and alpha-ketoglutarate dehydrogenase (alpha-KGDH) in addition to glucose-6-phosphate dehydrogenase (G6PDH) and cytochrome P4501A (CYP1A), measured as 7-ethoxyresorufin O-deethylase (EROD), in Baltic salmon yolk-sac fry after treatment with thiamine. Thiamine concentrations and activities of TK, alpha-KGDH and EROD were significantly lower (P<0.05) in M74 groups compared to controls (not developing M74) and family groups of thiamine injected females. In M74-developing groups the thiamine immersions reduced the mortality from 86 to 13% and restored thiamine concentrations and activities of TK, alpha-KGDH and EROD to levels slightly lower than the immersed controls. An interesting fact was that the controls showed significantly elevated (P<0.05) TK and alpha-KGDH-activities after immersions in thiamine, indicating that they also may have a stressed thiamine metabolism. The TK and alpha-KGDH-activities of unimmersed groups correlated significantly (P<0.05) with the thiamine content. We suggest that the low activities of TK and alpha-KGDH in M74 groups may be an integrative part in the pathogenesis of M74 development.
自1974年以来，洄游型波罗的海鲑鱼（Salmo salar）种群受到M74综合征的影响，导致瑞典补偿性育苗场中卵黄囊仔鱼大量死亡。M74已被证明是一种母系传播的硫胺素（维生素B1）缺乏症。本研究的目的是调查硫胺素与硫胺素依赖性酶转酮醇酶（TK）和α-酮戊二酸脱氢酶（α-KGDH）的肝脏活性之间的可能关系，此外还包括葡萄糖-6-磷酸脱氢酶（G6PDH）和细胞色素P4501A（CYP1A），以7-乙氧基异吩恶唑酮O-脱乙基酶（EROD）来衡量，这些指标在硫胺素处理后的波罗的海鲑鱼卵黄囊仔鱼中进行测定。与对照组（未发生M74）和注射硫胺素的雌鱼的家系组相比，M74组中的硫胺素浓度以及TK、α-KGDH和EROD的活性显著降低（P<0.05）。在发生M74的组中，硫胺素浸泡使死亡率从86%降至13%，并使硫胺素浓度以及TK、α-KGDH和EROD的活性恢复到略低于浸泡对照组的水平。一个有趣的事实是，对照组在硫胺素浸泡后显示出TK和α-KGDH活性显著升高（P<0.05），这表明它们的硫胺素代谢也可能受到了压力。未浸泡组的TK和α-KGDH活性与硫胺素含量显著相关（P<0.05）。我们认为，M74组中TK和α-KGDH的低活性可能是M74发病机制中的一个综合部分。
