Objective To establish influenza A and influenza B virus infection models in mice, systematically evaluate the pathogenic characteristics of different strains in vivo, so as to provide experimental tools for vaccine immunogenicity assessment and antiviral drug screening.Methods SPF-grade BALB/c mice were intranasally inoculated with gradient viral doses of seasonal epidemic virus strains A/H3N2, A/H1N1, B/Vic, and B/Yam circulating in the Northern Hemisphere 2021-2022.The body mass changes, mortality, and clinical symptoms were dynamically monitored for 7 days. Animals were euthanized on days 4 and 7 post-infection. Five lung lobes(left and right) were dissected for viral load quantification by qPCR and histopathological examination to determine the optimal modeling infection dose of each strain. The optimal dose was used for verification test, and the viral loads, pathological changes and inflammatory cytokine levels were measured 7 days after infection.Results Two days after infection with A/H1N1, B/Vic, and B/Yam strains, the body mass of mice began to decrease, and the viral loads in lung tissues reached the peak on the 4 th day after infection, accompanied by moderate interstitial pneumonia characterized by fibrinous exudates in alveolar spaces and inflammatory cell infiltration. The viral loads persisted until day 7 without decline after infection, and the pathological damage persisted. The viral load and pathological changes in different parts of the lung tissue of the same mouse were different, and individual differences were large. No significant body mass fluctuations were observed across all dose groups of A/H3N2 strain, the pulmonary viral loads remained below detection thresholds,and histopathology revealed no influenza-specific lesions, indicating inefficient replication in BALB/c mice. The optimal modeling infection doses of A/H1N1, B/Vic, and B/Yam strains were determined to be 1. 6 × 10~5, 8. 9 × 10~2, and 2. 5 × 10~4 TCID_(50),respectively. Verification experiments showed that 7 days after infection with A/H1N1, B/Vic, and B/Yam strains, mice all experienced body mass loss and corresponding clinical symptoms, and the viral loads in lung tissues were all more than6 lgcopies/??g RNA. Typical pathological changes of interstitial pneumonia were observed, accompanied by increased levels of key inflammatory cytokines such as TNF-α, IL-6, and IFNγ.Conclusion A/H1N1, B/Vic and B/Yam strains can establish stable infection models in BALB/c mice, which are suitable for vaccine efficacy assessments and preliminary drug screening. A/H3N2 strain has not been effectively replicated in mice, and ferret model can be used for related research.

AIM: To provide references for the non-clinical evaluation of therapeutic targets or drugs for retinoblastoma, fluorescently labeled Y79 cells are injected into the vitreous body of BALB/c-nu mice to establish a retinoblastoma model, and the Melphalan treatment group is used as a positive control, which is verified by fluorescence imaging technology.METHODS: BALB/c-nu mice were intravitreous injected with GFP transfected Y79 cells(1.0×107 cell/mL, 3 μL)to establish the model. On the 27th day, the mice were randomly divided into model control group and different doses of Melphalan groups(1, 3, 10 μg/eye groups)according to the fluorescence value of in vivo imaging, with vitreous body single administrated and ocular symptoms observed daily. Slit-lamp examination was performed at 12, 20, 29, 35, 42, 48, 55, 76, and 83 d after modeling. In vivo imaging was performed on 12, 20, 27, 41, 48, 55, 62, 69, 76, and 83 d. At the last treatment, the eyeball, brain and cerebellum tissues were removed for histopathological examination.RESULTS: From the sixth day of modeling, cloud-like substances could be seen in the eyes of the animals, and the cloud-like substances occupied the whole eyeball of the mice in the model control group at the later stage, accompanied by irregular growth of blood vessels. After 27 days of modeling, the fluorescence value was detected in all the animals, and the fluorescence value continued to increase with the extension of modeling time. The fluorescence value of the tumor reached the peak after 69-83 days of modeling. Histological examination showed severe proliferation of intraocular tumor cells in the model control group, and tumor cells were observed in the brain of 1 model animal. In the 10 μg/eye Melphalan group, the fluorescence value was significantly decreased at 17 d after administration. The fluorescence value of the 3 μg/eye Melphalan group was significantly inhibited at 59 d after administration. No tumor cells were found in the brain tissue of animals in all Melphalan groups.CONCLUSION: After vitreous injection of Y79/pCDH-LUC-copGFP cells in BALB/c-nu mice, significant ocular lesions and proliferation of tumor cells were observed in the eyes. Meanwhile, Melphalan intervention significantly inhibited tumor cells in a dose-dependent manner, indicating that the mouse model of retinoblastoma was successfully constructed.

Forsythiae fructus,a traditional Chinese medicine for heat clearing and detoxifying,is commonly used in clinic.It mainly contains phenylethanol glycosides,lignans,terpenoids,volatile oils,flavonoids and other chemical components.Numerous studies have confirmed that forsythiae fructus has anti-inflammatory,antibacterial,antiviral,anti-cancer and other pharmacological effects.Moreover,it has high safety.In this paper,the chemical composition,pharmacological action and safety of forsythiae fructus were reviewed.The aim of this study is to collect the relevant research achievements of forsythiae fructus,and to provide ideas and references for its further research and clinical application.