Mechanism of inflammatory responses and histopathological changes in Staphylococcus aureus induced bloodstream infections in mice
10.3969/j.issn.1000-484X.2016.04.024
- VernacularTitle:金黄色葡萄球菌经静脉和腹腔诱导小鼠血流感染的炎症反应和病理变化
- Author:
Dan WU
;
Shusheng ZHOU
;
Shijing HU
;
Bao LIU
- Publication Type:Journal Article
- Keywords:
Staphylococcus aureus;
Bloodstream infections;
Inflammation;
Cytokines;
Histopathology
- From:
Chinese Journal of Immunology
2016;32(4):556-562
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To establish mice models of Staphylococcus aureus bloodstream infections so as to investigate the inflammatory responses and histopathological changes in bloodstream infections (BSIs) mice.Methods:C57BL/6 mice were inoculated with S.aureus intravenously or intraperitoneally to induce BSIs.Survival rate , weight loss and murine sepsis scores ( MSS ) were ob-served.Blood samples and tissue homogenates were plated on agar to determine bacterial burden .Inflammatory proteins ( CRP,PCT) and cytokines ( IL-1β, IL-6 and TNF-α) were determined by ELISA kits.Histopathologic changes were also assessed by pathological inflammation scores(PIS),macroscopic and microscopic examination.Results: About 70% survival rate was observed in 4.5×108 CFU/ml S.aureus induced BSIs mice.Body weight decreased and sepsis scores increased significantly since 24 h post-infection in BSIs mice,and more prominent in IV group.The counts of WBC began to significantly increase at 3 h post-infection,while CRP and PCT levels peaked at 48 hours in IV and IP groups ( 60.80 ±5.63 vs 40.58 ±7.54 for CRP;6.796 ±1.16 vs 2.740 ±0.36 for PCT ) . Moreover,the levels of IL-1β,IL-6 and TNF-αin serum and tissue homogenates ( liver,lungs,and kidneys ) were significantly elevated in BSIs mice.Pathological changes in tissues (liver,lungs and kidneys) and higher pathological inflammation scores (PIS) were also observed in BSIs mice.Conclusion:Our study represents an effective approach for S.aureus BSIs model to mimic human sepsis.Our results demonstrated that inflammation protein (PCT,CRP) and cytokines(IL-6,IL-1βand TNF-α) play an important role in the in-flammatory response and histopathological changes during BSIs caused by S .aureus.
