Cannabinoid Receptor 2 Modulates Neutrophil Recruitment in a Murine Model of Endotoxemia

Figure 4

CB₂ knockout mice have comparable numbers of neutrophils and monocytes in the lungs following LPS challenge. Male C57BL/6J and CB₂ knockout mice (8–10 weeks old) were administered i.p. with 1 mg/kg LPS and innate immune cell recruitment to the lungs was studied at 2 and 8 hours. Lung homogenates were stained for neutrophils (CD45⁺Ly-6G^hiLy-6B.2⁺) and monocytes (CD45⁺Ly-6G^midLy-6B.2⁺) by flow cytometry. Representative dot plot graphs gated on CD45⁺ cells are shown from one C57BL/6J (a) and one CB₂ knockout (b) mouse for each time point. Pooled data from two independent experiments with 8-9 mice per group are shown for neutrophils (c) and for monocytes (d). (e–g) Proinflammatory mediator mRNA expression was measured in lung homogenates from wild-type and CB₂ knockout murine lungs at 2 hours by qRT-PCR. Data for Il6 (e), Ccl2 (f), and Cxcl1 (g) are pooled from two independent experiments with 8-9 mice per group and 4-5 mice per group per experiment. Mean + SEM are represented in all bar graphs and data were analysed with a one-tailed student t-test (e–g) or a two-way ANOVA with Sidak’s post hoc multiple comparisons test (b, d), .

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