RESUMO
Objective To establish a mouse model of acute liver failure induced by lipopolysaccharide /D-galac-tosamine ( LPS/D-GalN) .Methods The optimum dose of LPS/D-GalN was determined by i .p.injection of eight differ-ent doses of LPS and D-GalN into 40 female C57BL/6 mice and observation of their survival time .Then, 32 female C57BL/6 mice were i.p.injected with the optimal dose of LPS/D-GalN and sacrificed at 0, 1, 4, 8 hours after the injec-tion, 8 mice in each group.The control mice received saline injection .Hepatic changes were observed by pathology and se-rum ALT, IL-6, MCP-1 and TNF-αwere measured by biochemistry or flow cytometry .Results LPS (2.5 mg/kg) and D-GalN (0.3 g/kg) were determined as the optimal dose for the establishment of mouse model of acute liver injury .Com-pared with the control group , the hepatocellular damages were progressing in a positive correlation with the time course after LPS/D-GalN administration .The level of serum ALT was significantly increased after LPS/D-GalN administration ( P <0.001).The levels of inflammatory cytokines IL-6, MCP-1 and TNF-αwere increased and reached a peak at one hour after LPS/D-GalN administration and then decreased almost to that of the control group 8 hours later(P<0.001).Conclusions The mouse model of acute liver injury is successfully established by LPS /D-GalN administration , and provide an effective animal model for the study of pathogenic mechanisms of acute liver failure and evaluation of therapeutic drugs .
RESUMO
Objective To analyze and compare the pathological changes of lung tissue in mice infected with the novel H7N9 influenza virus and 2009 pandemic H1N1 influenza virus, respectively, and to preliminarily study the mecha-nisms of acute lung injury induced by those virus infection .Methods SPF 6-week old BALB/c mice ( body weight 18-20 g, male∶female=1∶1) (n=3 in each subgroup) were intranasally infected with H7N9 virus and H1N1 virus, respec-tively.The behavior and survival time of mice after virus infection were observed and the survival rates were analyzed .The heart, liver, spleen, lung, kidney, intestines, and brain were collected at indicated time points for histopathological exami-nation using H&E staining .The distribution of virus antigen was detected by immunohistochemistry .The neutrophil infiltra-tion was also observed .The correlation of lung injury with virus replication and host immune responses was analyzed .Re-sults The lung and spleen injury of mice infected with H 7N9 virus was slighter and their survival rate (100%) was high-er than those of mice infected with H1N1 virus.The damages of the lung and spleen in H1N1virus-infected mice were more severe than that in H7N9 virus-infected mice, and all the 10 mice in this group died within 9 days after virus inoculation . The distributions of both the virus antigens were mainly in the bronchial epithelial cells , a few stromal cells and alveolar ep-ithelial cells .The levels of virus replication in the two groups were not significantly different .There were more intense neu-trophil infiltration in the lung and inflammatory response in the H 1N1 virus-infected mice than those in the H7N9 virus-in-fected mice .Conclusions There are some differences of the pathological characteristics and extent of lung injury in the mice infected with H7N9 virus and H1N1 virus, respectively.The virus replication is a precipitating factor but not the deci-sive factor of the lung injury , and there is a close relationship between the host immune responses and acute lung injury .