低氧胁迫和螺原体感染对中华绒螯蟹存活和细胞凋亡的影响

为了探究低氧胁迫对螺原体(Spiroplasma eriocheiris)感染中华绒螯蟹(Eriocheir sinensis)的影响, 以中华绒螯蟹为研究对象, 在低氧胁迫后, 取中华绒螯蟹肝胰腺和鳃组织加入组织固定液, 进行HE染色。在低氧条件下使螺原体感染中华绒螯蟹, 计算螺原体拷贝数, 并对血淋巴细胞进行细胞凋亡、细胞坏死和线粒体膜电位检测。结果显示, 与对照组相比, 处于长时间低氧胁迫状态下的中华绒螯蟹肝胰腺组织疏松, 出现大量小空泡, 鳃轴结构弥散, 组织结构被破坏。此外, 低氧组的中华绒螯蟹感染螺原体后的死亡速度相对于常氧组明显加快, 血细胞内的螺原体数量、线粒体膜电位、血细胞凋亡率和坏死率相较于常氧组均显著升高。以上研究说明低氧胁迫可以加速螺原体的感染, 使河蟹死亡速度变快, 使血淋巴细胞凋亡和坏死更显著, 不利于河蟹的生理生化。

EFFECTS OF HYPOXIA STRESS AND SPIROPLASMA ERIOCHEIRIS INFECTION ON THE SURVIVAL AND APOPTOSIS OF ERIOCHEIR SINENSIS

The Chinese mitten crab (Eriocheir sinensis) is often caused by hypoxia to impact growth and immunity. E. sinensis tremor disease is caused by the pathogen Spiroplasma eriocheiris, which is highly contagious with a high mortality rate. To explore the effect of hypoxia stress and the S. eriocheiris infection on E. sinensis, the mortality rate and the histopathology of crab, the Spiroplasma copy number, apoptosis & necrosis and mitochondrial membrane potential in hemocytes were studied. The results showed that long-term hypoxia stress damaged hepatopancreas and gill tissues. Multiple vesicles appeared in the crab hepatopancreas after 8d hypoxic stress. The crab gill tissue was diffused after 8d hypoxia stress. The mortality of E. sinensis in hypoxia group under S. eriocheiris infection at 10d was 100%, meanwhile, the mortalities in normoxia group under S. eriocheiris infection at 10d and 12d were 50% and 70%, respectively. The mortality of E. sinensis in hypoxia group at day 12 (60%) was higher than the mortality in normoxia group (30%). These results reveal that the hypoxia could accelerate the crab dead under S. eriocheiris infection with increased copy number of S. eriocheiris in hemocytes and enhanced hemocytes necrosis rate (PI stain) and apoptosis rate (FITC/PI stain). Hypoxia increased the mitochondrial membrane potential in hemocytes under S. eriocheiris infection at 4d, 6d and 8d, and S. eriocheiris infection induced the mitochondrial membrane potential in hemocytes. These results indicate that hypoxia stress and S. eriocheiris infection have a synergistic harmful effects on the physiology and biochemistry of E. sinensis.