Study on cytokines level and extraintestinal injury in suckling mice infected with rotavirus

Objective: To establish the suckling mice model infected with intestinal rotavirus(RV),detect the serum levels of γ-interferon(IFN-γ) and interleukin(IL-17) in suckling mice,compare two kinds of cytokine changes at different time points,further investigate the relationship between cellular immunity and related cytokine,and understand the immunopathological features of RV infection for seeking a new method in preventing RV infection and extraintestinal injury in clinic.Methods: Simian RV strain SA-11 was cultured and amplified from rhesus monkey kidney cells(MA-104).Sixty clean grade BALB/c suckling mice,3 to 5 day-old,half of male and female,were randomly divided into the observation group and control group(30 cases each group).The observation group(RV infection model group) were poured with 100μL(1×10^-4) the TCD50 infectious titer of the SA-11 strain RV into stomach,and the control group were poured with 100 μL 0.9% sodium chloride injeetion into stomach.The day of virus inoculation was set as the day 0,and the suckling mice activities were observed after inoculation daily,and the RV antigen was detected in stool.After 3 and 8 days of inoculation,the serum levels of IFN-γ and IL-17 were measured.The suckling mice were sacrificed,and the pathological changes of heart and liver were observed using light microscopy.Results: The serum level of IFN-γ in observation group after 3 days of infection was higher than that in control group(P<0.05),and the difference of which after 8 days of infection between two groups was not statistically significant(P>0.05).The difference of the serum level of IL-17 between two groups after 3 days of infection was not statistically significant(P>0.05),and the serum level of IL-17 in observation group after 8 days of infection was significantly higher than that in control group(P<0.05).Under light microscope,most hepatocytes swelling,median and severe vacuolar degenerating,spotty lymphocytes infiltrating,myocardial cells cloudy swelling,myocardial interstitial edema and endocardial myocardial layer lymphocytes infiltrating were found in observation group after 3 days of infection.After 8 days of infection,the individual liver cells slightly swelling,mild vacuolar degenerating and generally normal myocardial cells were identified in observation group.No obvious changes in liver and heart was found in control group.Conclusions: In intestinal rotavirus infection,especially in early period,the expression of IFN-γ predominates,but it is mild,and the expression of IL-17 predominates in later period.IL-17 may play a role on controlling the RV,and repairing the parenteral organs damage.