| Novel goose astrovirus infection is characterized by the deposition of urate in the viscera,muscle and joint cavity of goslings,which has brought serious economic losses to the goose industry in China.Four novel goose astroviruses(DY-19,HR2105/01,WQ and ZM)were isolated in our laboratory from 2019 to 2022,which can cause morbidity and even death of goslings.In this study,we found that the novel goose astrovirus DY-19,HR2105/01,WQ and ZM strains isolated in the laboratory had different pathogenicity to gosling,and further explored the differences in host immune responses caused by the above strains.By using transcriptome sequencing of kidney tissues of DY-19 group and ZM group,the differences in kidney transcripts between the two groups of infected gosling were analyzed.The significantly differentially expressed genes were obtained for subsequent research,and the results laid a foundation for exploring the pathogenic mechanism of the new goose astrovirus.The results showed that the mortality of DY-19,HR2105/01,WQ and ZM strains were50%(10/20),30%(6/20),50%(10/20)and 0%,respectively.Anal and pharyngeal detoxification began on the 3rd day after challenge,and the peak of detoxification lasted until the 9th day after challenge.The biochemical indexes such as uric acid,creatinine,blood calcium and blood phosphorus in the challenge group were significantly increased.The main infected organs of the four strains were kidney,spleen and liver,and the viral load of each organ in ZM group was lower than that in other groups.Histopathological examination showed renal tubular epithelial cell necrosis and inflammatory cell infiltration.TUNEL assay showed that the apoptotic signal in DY-19 group was significantly more than that in ZM group.The results showed that the infectivity of astrovirus was the highest within 3 to5 days after the onset of disease.The pathological changes caused by infection were related to the biochemical indexes of the host.The pathogenicity of DY-19,HR2105/01 and WQ strains was higher than that of ZM strains.The expression levels of IL-6,IFN-α,RIG-I,TLR3,OSAL,Mx1,Caspase1,Bax,BCL2 and other immune-related indicators in the spleen tissue were detected by real-time PCR.The results showed that the m RNA levels of the above indicators in the infected goslins were significantly higher than those in the control group.The expression levels of each index in ZM group were generally lower than those in other groups.The m RNA expression levels of uric acid synthesis protein in liver and uric acid transporter in kidney were higher and lower than those in the control group,respectively.The expression levels of these two proteins were related to uric acid production and metabolism.To explore the effect of novel goose astrovirus infection on the expression of host transcripts,RNA was extracted from the kidney tissue of dead goslins in DY-19 group and ZM group for transcriptome sequencing.DY-19 group was used as the experimental group,and ZM group was used as the control group.The Clean reads of each sample accounted for more than 90% of the Raw reads,and the GC base content was about 50%,indicating that the sequencing data were reliable.A total of 2758 genes were up-regulated and 3761 genes were down-regulated.By combining the expression of transcripts with GO function analysis and KEGG pathway analysis,a total of eight specific genes were screened out,which could be used for subsequent research.In summary,by studying the differences in animal pathogenicity and the regulation of host immune response among multiple goose astrovirus strains,we explored the specific immune response mechanism caused by novel goose astrovirus.To provide a theoretical basis for exploring the pathogenic mechanism of novel goose astrovirus by transcriptome sequencing. |
