摘要
硫化物是水产养殖过程中常见的水体污染物之一。为探讨水体硫化物胁迫对虾类血细胞的毒性影响,以不同浓度(0.5 mg/L,2.0 mg/L)的硫化物对凡纳滨对虾(Litopenaeus vannamei)进行胁迫,于胁迫后6、12、24和48 h取血淋巴,应用流式细胞术测定血细胞的总数(THC)、活性氧(ROS)含量、一氧化氮(NO)含量以及凋亡率。结果显示,经0.5 mg/L硫化物胁迫48 h后,对虾THC显著下降至11.78×10~6个/mL,为对照组的72.7%(P<0.05),ROS含量为对照组的225.2%(P<0.05),血细胞凋亡率显著上升至7.42%(P<0.05);经2.0 mg/L硫化物胁迫6 h开始,对虾THC呈现显著的下降(P<0.05),血细胞ROS含量和凋亡率显著提高(P<0.05);表明硫化物胁迫刺激对虾血细胞产生大量ROS,诱导血细胞凋亡,从而导致THC下降,这一过程可能是硫化物导致虾类细胞免疫下降的重要机制;随着硫化物浓度的升高,其细胞毒性作用明显提高。血细胞NO含量在2.0 mg/L硫化物胁迫12和48 h时显著升高(P<0.05),推测NO可能在硫化物胁迫防御调控中起着信号因子的作用。
Sulfide is one of the common water pollutants in shrimp farming ponds and is highly toxic to shrimp. In this study we investigated the effects of sulfide toxicity on the haemoeytes of shrimp and discussed the toxic mecha- nism, aiming to provide a theoretical basis for preventing and controlling sulfide pollution in shrimp farms. Litope- naeus vannamei （ 8.32 ± 0.72） g, commonly known as white shrimp, were acclimated for a week at 22 - 24℃, pH 7.9 - 8.0 and salinity of 20 g/kg. Healthy shrimp were then randomly selected for different sulfide exposures （0, 0.5 and 2.0 rag/L） , with 20 shrimp per group and each group in triplicate. After exposure, in shrimp breeding barrels, for 6, 12, 24 and 48 h, the total haemocyte count （THC）, reactive oxygen species （ROS） production, NO production and apoptotic cell ratio of haemocytes were determined using flow eytometry （FCM）. The THC of the shrimp was initially （ 159. 3 _＋ 12. 0 ） x 105 eells/mL and the count decreased significantly to 117.8 ~ 105 cells/mL after 48 h exposure to 0.5 mg/L sulfide （72.7% of the control group,P 〈0.05）. The shrimp THC also decreased significantly after 6 hr at 2.0 rag/L, reaching the minimum value after 12 h （66.3 % of the control group） and then increasing slowly to 77.5% of the control group after 48 h. After 48 hr at 0.5 mg/L sulfide, ROS production in the haemocytes was 225.2% that of the control （ P 〈 0.05 ） and ROS production at 2.0 mg/L sulfide treatment increased significantly （ P 〈 0.05 ） after 6 h, increasing to the maximum value after 12 h （335.3 % of the control）. No significant change was observed in NO at 0.5 mg/L sulfide, but NO did increase significantly （ P 〈0.05 ） after exposure to 2.0 mg/L sulfide for 12 （ 140.3% of control） and 48 h （ 134.8% of control）. The apoptosis rate of haemoeytes in the control group was 3.36% - 4.34%, rose to 7.42% （ P 〈 O. 05 ） after 48 h at 0. 5 mg/L sulfide, and was highest at 9.55 % （ P 〈 0.05 ） after 24 hr at 2.0 mg/L sulfide. These results indicate that sulfide exposure causes an overproduction of ROS and increases the rate of apoptosis in haemocytes, reducing the THC and consequently affecting the immune function of L. vannamei. This mechanism is likely responsible for the observed decline in shrimp immune function associated with sulfide toxicity and there is a clear dose-response relationship.
出处
《水生态学杂志》
CSCD
北大核心
2017年第3期97-102,共6页
Journal of Hydroecology
基金
国家自然科学基金(31500326)
广东省自然科学基金(2014A030310185)
广东省普通高校青年创新人才项目(2014KQNCX056)
广东省普通高校特色创新项目(2015KTSCX019)
中国热带农业科学院基本科研业务费专项资金(1630052016011和1630052016021)
关键词
硫化物
血细胞
凋亡
凡纳滨对虾
sulfide
haemocyte
apoptosis
Litopenaeus vannamei
