| Fish is poikilothermal animal,which lacks the body temperature control system,and the body temperature will change with the change of water temperature.Temperature is a very important abiotic factor in the process of fish growth,which affects the life activities of fish.Fish will produce a tertiary response to low temperature pressure.Fish is an ideal model to study the effect of temperature on immunity,which has a complete vertebrate immune system,including innate immunity and adaptive immunity.At present,the study on the molecular response of fish to low temperature stress and adaptation to low temperature is not clear.The immune-related genes and mechanisms of the specific effects of low temperature need to be explored.This study took zebrafish as the research object to explore the effects of low temperature on zebrafish behavior and gene expression,which is of great significance to the study of cold resistance of zebrafish.After two weeks of low temperature stimulation,the survival rate of zebrafish decreased and the parade was slow.The liver,foregut,midgut,hindgut and muscle were extracted and their transcriptomes sequenced.GO and KEGG analysis showed that there were differences in the expression of immune-related genes under low temperature stress,and the expression of many kinds of cytokines and chemokines changed.In order to further explore the effect of low temperature on the immunity of zebrafish,LPS stimulated zebrafish and found that adaptive immunity and innate immunity related molecules responded slowly in liver at low temperature.In the intestinal tract,a variety of immune factors were up-regulated at low temperature,which could lead to immune response.Therefore,the morphological and histological analysis of zebrafish hindgut showed that LPS stimulation caused cell infiltration and acid mucin to increase in zebrafish intestinal tissue at low temperature,which was more likely to cause inflammation.Combined with transcriptome analysis,the expression of many inflammation-related factors changed at low temperatures.It was worth noting that compared with the gene expression at normal temperature,the expression of DUSP2 gene was up-regulated in all tissues at low temperature.The transcription factor STAT3 in higher animals promotes inflammation,and the interaction between DUSP2 and STAT3 was found in this study.The phosphorylation of STAT3 decreased with the increase of DUSP2 expression.DUSP2 may inhibit the STAT3 inflammatory signaling pathway by dephosphorylation of STAT3.DUSP2 may act as a negative feedback regulator of inflammation and coordinate the dynamic balance of inflammation in fish. |
