PLD1 deficiency reduces disease severity and joint inflammation in collagen-induced arthritis (CIA) mice. (A) Clinical arthritis scores were determined in CIA-challenged PLD1+/+ and PLD1−/− mice. (B) Incidence of CIA, as scored in all paws. (C) Hematoxylin and eosin staining of knee joint sections from the indicated mice at day 42. (D) Histological assessment of the pathological features of mice knee joints at day 42. (E) Representative micro-computerized tomography images of femurs and knee joints of mice at day 42 (top—transverse sections of metaphysis; middle—three-dimensional reconstructed knee joint; bottom—magnified view) (F) Histomorphometric analysis of the bone for each group, showing bone volume (BV)/tissue volume (TV) ratio, trabecular bone thickness (Tb.Th), trabecular separation (Tb.Sp), and trabecular number (Tb.N). n = 15 per group. * p < 0.05. Quantitative results are shown as mean ± standard error of the mean (SEM).