亚硝酸盐和微塑料胁迫对凡纳滨对虾鳃中免疫、解毒代谢和渗透调节相关指标的影响

Effects of nitrite and microplastic stress on immune,detoxification metabolism and osmoregulation-related indicators in gills of Litopenaeus vannamei

鳃是对虾重要的呼吸器官,是亚硝酸盐毒性效应的主要靶器官,也是微塑料主要富集的部位之一。鳃组织参与了对虾渗透调节、氮排泄、免疫功能等生理过程,对对虾维持机体健康具有重要意义。为研究亚硝酸盐和微塑料单因素及复合胁迫对凡纳滨对虾(Litopenaeus vannamei)鳃组织生理功能的影响,将对虾分为对照组、20 mg·L^(−1)亚硝酸盐胁迫组(NIT)、10μg·L^(−1)微塑料胁迫组(MP)、20 mg·L^(−1)亚硝酸盐和10μg·L^(−1)微塑料复合胁迫组(NM),于第14天测定对虾鳃中相关指标变化。结果显示:1)氧化应激指标丙二醛(MDA)、过氧化氢(H_(2)O_(2))浓度及抗氧化酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)活性在胁迫后发生不同程度的改变;2)解毒代谢指标细胞色素P450基因(CYP450)和谷胱甘肽S-转移酶基因(GST)相对表达水平在胁迫后发生不同程度的紊乱;3)渗透调节指标如离子转运酶液泡型ATP酶(VATP)、Na^(+)/H^(+)交换体7(NHE7)、Na^(+)/K^(+)-ATP酶亚基α(NKA-α)、Na^(+)/K^(+)-ATP酶亚基β(NKA-β)、碳酸酐酶(CA)和水通道蛋白TIP4-1(TIP4)、钙通道蛋白1(CCP)、氯通道蛋白2(CLC)、水通道蛋白(AQP)基因的相对表达水平在胁迫后发生不同程度的紊乱;4)细胞凋亡因子基因(CASP-3)相对表达水平在3个胁迫组均显著降低(P<0.05)。由此推断,亚硝酸盐和微塑料胁迫会诱导凡纳滨对虾鳃中免疫、解毒代谢和渗透调节相关指标变化,进而影响其正常的生理功能。

Gill is an important respiratory organ of prawns,the main target organ of nitrite toxicity effect,and also one of the main enrichment sites of microplastics.The gill tissue participates in the physiological processes of prawns such as osmoregulation,nitrogen excretion,immune function,etc.,which is important for maintaining the prawns'health.In order to investigate the effects of single and combined stress of nitrite and microplastics on the physiological functions of gill tissues of Litopenaeus vannamei,we designed the control group,20 mg·L^(−1) nitrite stress group(NIT),10μg·L^(−1) microplastic stress group(MP),20 mg·L^(−1) nitrite and 10μg·L^(−1) microplastic composite stress group(NM),and then measured the changes of immune and osmotic regulation in gills of shrimps on the 14^(th) day.The results show that:1)The oxidative stress indicators such as the contents of malondialdehyde(MDA)and hydrogen peroxide(H_(2)O_(2)),and the activities of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GPx)changed at different degrees after the stress.2)The detoxification metabolic indicators such as the relative expression levels of cytochrome P450(CYP450),glutathione S-transferase(GST)and apoptosis factor(CASP-3)were disturbed at different degrees after the stress.3)The relative gene expression levels of the osmoregulation indexes such as ion transporters(VATP,NHE7,NKA-α,NKA-βand CA)and channel proteins(TIP4,CCP,CLC and AQP)occurred at different degrees of disorder after the stress.4)The apoptosis index sucha as the relative expression level of apoptosis factor(CASP-3)gene decreased significantly in the three groups(P<0.05).Thus,it is inferred that nitrite and microplastic stress can induce the changes of immunity,detoxification metabolism and osmotic regulation in the gills of L.vannamei,affecting its normal physiological functions.