Figure 2. Arthritis dysregulates intestinal lipid mediator profiles.

Arthritis was initiated by injection of K/BxN serum (50 μL per mouse, i.p.; days 0 and 2). On day 8 ilea were harvested from arthritic and naive mice and lipid mediators identified and quantified using lipid mediator profiling (see Methods for details). (A) Representative multiple reaction monitoring (MRM) traces for identified lipid mediators. (B) Representative MS/MS spectrum employed for the identification of RvD5_{n-3 DPA}; inset, diagnostic ions; M, molecular mass. (C) Orthogonal partial least squares discriminant analysis (oPLS-DA) of intestinal lipid mediator profiles. Cumulative tissue concentrations for SPMs (i.e., arachidonic-, eicosapentaenoic acid–, n-3 docosapentaenoic– [DPA–], and docosahexaenoic acid–derived [DHA-derived] proresolving mediators) (D), RvD_{n-3 DPA} (i.e., RvD1_{n-3 DPA}, RvD2_{n-3 DPA}, and RvD5_{n-3 DPA}) (E), and RvD5_{n-3 DPA} (F). Results for A and B are representative of n = 24 mice; for C are representative of n = 8 mice per group; for D–F are mean ± SEM for n = 8 mice per group from 2 independent experiments; *P ≤ 0.05 versus naive using Mann-Whitney U test. Results are expressed as pg/10 mg tissue.