Objective A model for studying oral ulcers induced by betel nut-extract was constructed in rats.Changes in the structure and diversity of oral flora were observed to explore the involvement of oral flora and local inflammatory factors in the pathogenesis of oral ulcers induced by betel nut-extract and to provide theoretical support for the prevention and treatment of oral ulcers in the clinic.Methods Thirty SD rats were randomly divided into normal,model and intervention groups(Guilin watermelon cream,8 mg/d for 7 days),with 10 rats/group.The oral mucosa of rats was subcutaneously injected with 10 g/mL of betel nut-extract to generate an oral ulcer model.The histomorphological changes were observed,and ulcer area and ulcer scores were assessed.Local oral tissue tumor necrosis factor-α(TNF-α),interleukin(IL)-2 and IL-8 levels were determined.Oral mucosal tissues were sampled for HE staining and analyzed for the structural distribution of oral flora and the diversity of microbial communities using high-throughput sequencing method.Results Compared with rats in the normal group,those in the model group had an increased ulcer area,significantly increased ulcer scores(P＜0.01),and significantly increased levels of TNF-α,IL-2 and IL-8 in the oral mucosal tissues(P＜0.01).The amount Streptococcus(P＜0.05)and Veillonella(P＜0.001)in the oral saliva of the model group rats was significantly reduced.The model group rats showed oral mucosal epithelial cell hyperplasia or focal necrosis,mucosal lamina propria edema,and hemorrhage accompanied by mass neutrophil and monocyte infiltration.Compared with the model group rats,the intervention group rats had significantly reduced ulcerated area(P＜0.05,P＜0.01)and ulcer scores(P＜0.05).And oral mucosal tissue levels of TNF-α(P＜0.01),IL-2(P＜0.05)and IL-8(P＜0.05),as well as significantly increased Streptococcus(P＜0.001)and Veillonella(P＜0.01)and significantly reduced Staphylococcus(P＜0.01)in the oral saliva.The degree of lesions in the oral mucosal tissues was significantly improved in the intervention group.Conclusions Betel nut-extract can be used to successfully reproduce a rat model of oral ulcer,and it is speculated that the development of oral ulcers after exposure to betel nut-extract may be related to an imbalance in the oral flora and local tissue inflammatory mediators.

Objective This study established a model of invasive Aspergillus niger lung disease in immunosuppressed rats to provide theoretical support for the pharmacodynamic evaluation of anti-invasive pulmonary aspergillosis drugs and mechanism studies.Methods Sixty SD rats were randomly divided into a normal control group;cyclophosphamide control group,and cyclophosphamide+fungal infection low,medium,and high dose groups,with 12 animals in each group.General clinical observations were performed daily,and the serum levels of immunoglobulin(Ig)G and IgM and galactomannan(GM)were detected by ELISA on the 3rd and 7th days of modeling.Simultaneously,the ratio of CD4+and CD8+cells,content of white blood cells(WBCs)and neutrophils(Neu)in peripheral blood,the Aspergillus niger load in alveolar lavage,and morphological changes to rat lung tissue were observed.Results Rats in the cyclophosphamide control and cyclophosphamide+fungal infection groups showed reduced voluntary activity and erect hair after modeling,and rats in the cyclophosphamide+fungal infection group also had shortness of breath and audible wet rhonchi in the lungs.Compared with the normal control group,rats in the cyclophosphamide control group showed significant reductions in the levels of CD4+,WBC,Neu,IgG,and IgM in the blood,and their proportion of CD8+cells was significantly higher(P＜0.05,P＜0.01).Compared with the cyclophosphamide control group,rats in the cyclophosphamide+fungal infection medium-and high-dose groups had significantly reduced blood levels of IgG,IgM,and CD4+cells(P＜0.05,P＜0.01);while the cyclophosphamide+fungal infection low-,medium-,and high-dose groups had significantly reduced blood levels of WBC and Neu(P＜0.05,P＜0.01).Additionally,rats in the cyclophosphamide+fungal infection medium-and high-dose groups had significantly increased blood CD8+cells(P＜0.05,P＜0.01),Blood GM levels and the alveolar lavage Aspergillus niger load were significantly increased in rats in the cyclophosphamide+fungal infection low-,medium-,and high-dose groups compared with the cyclophosphamide control group(P＜0.05,P＜0.01).The lung tissues of the cyclophosphamide+fungal infection low-,medium-,and high-dose groups showed mycelial distribution and destruction of alveolar epithelium,increase of bronchial epithelial cup cells in the alveoli,and infiltration of inflammatory cells,and the degree of lesions was positively correlated with the modeling dose.Conclusions In this study,we used Aspergillus niger combined with cyclophosphamide immunosuppressant to construct a model of invasive Aspergillus niger lung disease.The duration of the disease was positively correlated with the concentration of bacterial fluid and modeling time,confirming that cellular immunity plays an important role in the pathogenesis of the disease.At the same time,Ig can also affect the development of invasive pulmonary aspergillosis,and it is speculated that the pathogenesis may be related to the level of Ig produced by humoral immunity.