The effects of IL-18 on the expression levels of IL-18Rα and CD63 in peritoneal lavage fluid macrophage subsets of sepsis mice

Objective To investigate IL-1β and IL-10 levels in peritoneal lavage fluid (PLF), the expression of IL-18Rα and CD63 on type I macrophages (M1) and type II macrophages (M2) in sepsis mice, and the effects of IL-18 on these parameters.Methods The sepsis mouse model was established by intraperitoneal injection of cecal slurry. Spleen and PLF were collected. Hematoxylin and eosin staining was performed to examine spleen inflammation, and flow cytometry was used to detect IL-18Rα and CD63 expression on M1 and M2. PLF IL-1β and IL-10 were measured by liquid chip technology, and the Pearson correlation analysis was performed between IL-1β and the ratios of M1 and IL-18Rα+ M1, and between IL-10 and M2, CD63+ M2 and IL-18Rα+ M2.Results It was observed in sepsis and IL-18-pretreated mice that the size of spleen white pulp and inflammatory cell infiltration around the splenic envelope increased. Expression of CD63 and IL-18Rα on M1 and M2 macrophages was elevated. PLF IL-1β and IL-10 levels increased, with IL-1β highly positively correlated with the ratios of IL-18Rα+ M1, and IL-10 highly positively correlated with the ratios of CD63+ M2 and IL-18Rα+ M2..Conclusion Briefly, increased expressions of IL-18Rα and CD63 on M1 and M2 of sepsis and IL-18-pretreated mice, and the strong positive correlations between elevated PLF IL-1β and IL-10 levels with the ratios of IL-18Rα+ M1 and IL-18Rα+ M2, suggest that IL-18 may play an important role in the dysregulated inflammation response of sepsis by inducing M1 and M2 activation through IL-18Rα.