肺炎支原体R414北京流行株感染小鼠模型的研究OA

Objective To establish a murine Mycoplasma pneumoniae(Mp)model by intranasally infecting BALB/c mice with the reference strain FH and the Beijing epidemic strain R414,and to evaluate the similarities and differences in pathogenicity and immunopathology between R414 and the reference strain FH.Methods 3-week-old and 8-week-old BALB/c mice were intranasally infected with FH or R414 strains.Control groups received intranasal 0.9％sodium chloride solution.Pathogen load,pathological changes,and transcriptome alterations in lung tissues,as well as peripheral blood immune cell and cytokine levels,were measured on days 6,9,and 12 post-infection.Results Mice infected with Mycoplasma pneumoniae exhibited features of acute pneumonia(high pathogen load and significant inflammation on day 6,subsiding by days 9～12).No significant differences were observed between FH and R414 strains in pathogen load.Following FH infection,cellular immunity in 8-week-old mice was activated earlier than in 3-week-old mice;moreover,the number of differentially expressed genes in the transcriptome of 8-week-old mice significantly exceeded that of 3-week-old mice.6 d after R414 infection in 3-week-old mice,peripheral blood IP-10 levels increased.6 d after R414 infection in 8-week-old mice,the proportion of monocytes increased,and TNF-αlevels rose.The R414 strain induced a"viral response"pathway in 3-week-old mice,while in 8-week-old mice,it primarily activated pathways such as the"IL-17 signaling pathway"and"neutrophil chemotaxis".Conclusions The R414 strain induced differentiated host immune responses compared to the reference strain.These differences were correlated with the age of the mice and warrant further investigation.