Figure 3.

LPC16:0 injections into mouse ankle are not associated to peripheral nerve sprouting, inflammation, nor bone alterations. (A–B) Analysis of CGRP and CD68 expression in the ipsilateral tibiotarsal joint at D28, following intra-articular administrations of LPC16:0 (10 nmol) or vehicle in male mice. Top, representative photomicrographs of CGRP (A) and CD68 (B) staining in vehicle and LPC16:0-treated mice. Bottom, quantification of CGRP-positive fibers (A) in 2 ROIs (570 × 570 µm) and of CD68-positive cells (B) in one ROI (2500 × 2500 µm) from the ipsilateral tibiotarsal joint of vehicle and LPC16:0-injected mice. Results are expressed as a mean intensity (n = 4 for each group, no significant differences, Mann–Whitney tests). (C–D) Evaluation of the effect of LPC16:0 (10 nmol) or vehicle on inflammation and bone remodeling using in vivo fluorescent imaging for metalloprotease (MMP680) activity at D7 (C) and cathepsin K activity at D14 (D), respectively, in the ipsilateral and contralateral hind paws of male mice. Upper panels, illustrations; Lower panels, MMP680 ratio quantification (C) and cathepsin K activity ratio quantification (D). Data from n = 5 animals per group (no significant differences, Kruskal–Wallis tests followed by Dunn multiple comparison tests). (E–H) Relative levels of IL6 (E), Tnf (F), Apc5 (TRAP) (G), and Tnfsf11 (RANK-L) (H) messenger RNA expressed in the ipsilateral joint, determined by quantitative polymerase chain reaction after intra-articular injections of LPC16:0 (10 nmol, D14 and D28), CFA (D14), and vehicle (D14/D28; n = 4-6 for each group, **P < 0.01, Kruskal–Wallis tests followed by Dunn multiple comparison tests). CFA, complete Freund adjuvant; LPC, lysophosphatidylcholine; ROI, region of interest.