Analysis Of Transcription Level Of Interferons In Infection Model Of Canine Adenovirus Type Ⅰ Virulent Strain Infercted-canine

Infectious canine hepatitis(ICH)can be caused by canine adenovirus type I infection in dogs,which is characterized by high infectivity,high morbidity and high lethality.It has caused great harm and economic losses to dog farm.The aim of this study was to establish a canine CAV-1 infection model for evaluating the efficacy of vaccines and drugs of ICH.Firstly,we established a series of detection methods of CAV-1 in this experiment,including molecular biology detection(PCR and q PCR)and serological detection(IFA and HI).Secondly,we established an infection model in 2-month-old ordinary beagle dogs.Dogs were inoculated by intramuscular injection with CAV-1 at the same dose(105.7 TCID50/2 m L)and tested for detoxification,tissue viremia and viremia.There were different degrees of clinical symptoms,gross lesions and histological viral distribution in three infected dogs: 1.Dogs with low maternal antibody level and light weight had the most obvious clinical symptoms,the body temperature increased fastest and obvious hematochezia.The virus spread most widely in the body and the virus content in the tissues was the highest;2.Dogs with low maternal antibody and heavy weight or high maternal antibody and light weight showed no obvious clinical symptoms;3.Histological distribution of CAV-1 indicates that the dose of virus inoculation per weight and the maternal antibody of dogs should be taken into account in the establishment of canine CAV-1 infection model,that is,the background quality of experimental animals must be taken into account in the preparation and evaluation of the disease model.A 2-month-old beagle dog model of CAV-1 was established by intramuscularly injected with CAV-1 strain of 105.2TCID50/kg into the hind limbs.Various indicators showed that the body temperature reached the highest value at 2 dpi,and clinical symptoms showed stool blood at 2 dpi and mild diarrhea at 6 dpi,and the detoxification situation showed that detoxification of oral cavity began at 10 dpi,and virus content in blood was the highest at 3 dpi,the tissue infected with CAV-1 is mainly distributed in thymus,inguinal lymph nodes,submandibular lymph nodes,mesenteric lymph nodes and liver,the titer of antibody at 12 dpi was 1: 320 by using HI test.In order to explore the dominant role and potential medicinal value of interferon(IFN)in dogs infected with CAV-1,we successively detected the transcription levels of IFN in Madin darby canine kidney(MDCK)infected with CAV-1 in vitro,and blood and liver of beagle dogs infected with CAV-1 in vivo.The results showed that IFN-α was higher transcription level than others in MDCK cells treated with CAV-1,and IFN-λ1 and IFN-λ3 were higher transcription level than others in MDCK cells treated with Poly I:C and they might play an important role.In vivo,IFN-βR,IFN-λ1R and IFN-λ3R were higher transcription level than others in peripheral blood of infected dogs,and IFN-λ1R was higher transcription level than others in the liver of infected dogs.This study suggests that the role of interferon III should be considered more in the treatment of canine infectious hepatitis.