Study On Primary Hepatocytes And Liver Damage Of Ducklings Infected With DHAV-1

The liver is an important organ of humans and animals involved in a variety of metabolic processes. A variety of pathogenic factors can act on the liver directly or indirectly,leading to its abnormal structure or/and function.These factors mainly include pathogenic microorganism,toxin and drug.DHAV-1 can cause acute death of ducks within 4 weeks, combined with the symptoms such as hepatorrhagia, hepatocyte necrosis,bile duct epithelial hyperplasia and fatty degeneration of the liver.DHAV-1 can be propagated in chicken embryo chorioallantoic membrane, chicken embryo fibroblasts, duck embryo kidney cell or hepatocyte and it usually caused cytopathic effect.Due to the different nature of the pathogenic factor,the mechanism of effects on the liver is not the same way.In the research on liver damage mechanism,we found that ducklings infected with DHAV-1 would have abnormal lipid metabolism,high blood cholesterol,low blood sugar and increased fat.Matrix metalloproteinases 9 and Notch1 could cause hepatorrhagia,hepatocyte necrosis and bile duct epithelial hyperplasia in the pathological condition.On the base of DHAV-1 infection model of ducklings,we try to find the mechanism of the liver damage in ducklings infected with DHAV-1.1. We established the DHAV-1 infection model of duck primary hepatocyte successfully.QPCR detection the mRNA expression of DGAT2,ATGL,MTP in duck primary hepatocyte and ducklings infected with DHAV-1 were carried on.It showed that DGAT2 and ATGL expression were up-regulated in the duck primary hepatocyte infected with DHAV-1,meanwhile MTP down-regulated in the liver post-infection.The FFA levels in the culture supernatant of infected cells were the minimum at 8h and up-regulated at 24 h. In the ducklings, mRNA expression of ATGL and DGAT2 expression were up-regulated in the liver,MTP down-regulated at 12 h post-infectein and up-regulated at 24 h post-infection, after that which were up-regulated all the rest time.The results showed that the fat accumulated in duck primary hepatocyte and TG accumulated in the ducklings liver,and MTP play an important role in the accumulation of TG.2.The mRNA expression of MMP-9,NF-κB,PECAM-1,Jagged1,Notch1 and Notch2 were detected in the duckling livers infected with DHAV-1 by the method of QPCR and the protein expression of MMP-9 by the method of Western Blot.It showed that the mRNA expression of NF-κB was up-regulated at 24 h post-infection and there were both statistically significant differences between the control and inoculated ducklings.After 24 h,NF-κB expression was up-regulated all the time.The mRNA expression of MMP-9 up-regulated from 24 h post-infection arrived on the maximum value at 24 h post-inoculation.The protein expression of MMP-9 was up-regulated at 24 h post-infection,however it was down-regulated at 36 h and 48 h post-infection.The mRNA expression of PECAM-1 was relatively stable at 12 h to 36 h,and there was a little change between control group and infected group.Then it was down-regulated at 48 h and stable at 72 h post-infection. The mRNA expression of Notch2 and Jagged1 were down-regulated all the time post-infection,Notch1 expression was up-regulated all the time and it were maximum at 72 h.The results showed that NF-κB and MMP-9 and PECAM-1 were related to the liver hemorrhage and necrosis in the ducklings infected with DHAV-1 and Notch1 involved in the liver biliary epithelial cells proliferation in the ducklings infected with DHAV-1.