Histopathological and macroscopical evaluation of glucose-6-phosphate isomerase (G6PI) arthritis severity. (a) Acute murine G6PI-induced arthritis (day 13) provokes a massive accumulation of mainly polymorphonuclear cells (right arrow) and induces erosive processes (left arrow). Hematoxylin-and-eosin staining at original magnifications of ×40 and ×400 is shown. B, bone; C, cartilage; CI, cellular infiltrate; M, muscle. (b) Histopathological semiquantitative assessment of paw sections revealed a maximum of acute inflammation 13 and 21 days after arthritis induction, whereas chronic inflammation parameters were present past day 13. Total inflammation as the sum of acute and chronic parameters was at a maximum at days 13 and 21 and decreased at day 35 (n = 6 to 9 per time point). (c) Macroscopic scoring of paw swelling showed a maximum of inflammation at day 13 after experimental arthritis induction and gradual decreases at days 21 and 35.