Blockade of poly(ADP-ribose) synthetase inhibits neutrophil recruitment, oxidant generation, and mucosal injury in murine colitis  Basilia Zingarelli, Csaba Szabó, Andrew L. Salzman  Gastroenterology  Volume 116, Issue 2, Pages 335-345 (February 1999) DOI: 10.1016/S0016-5085(99)70130-7 Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 1 Severity of TNBS-induced colitis is reduced in PARS−/− mice. (A) Survival is significantly improved in TNBS-treated PARS−/− mice in comparison to the high mortality rate of the wild-type group. (B) Weight loss (expressed as percent of initial body weight lost) is significantly reduced after TNBS in PARS−/− mice. (C) Colon damage was scored on a 0 (normal) to 8 (severe) scale by 2 independent observers and was markedly reduced in PARS−/− mice. Each data point is the mean ± SEM of 4–20 animals for each group. *Significantly different from TNBS-treated wild-type mice (P < 0.05). 2, PARS+/+; ■, PARS−/−. Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 2 Time course of changes in colonic architecture after TNBS administration in PARS+/+ mice. (A) Representative colonic sections from nontreated mice showed normal architecture (day 0). At days (B) 1 and (C) 2 after TNBS administration, a marked disruption of the structure occurred starting from the epithelium toward the submucosa. At days (D) 3 and (E) 4, the extensive mucosal necrosis was associated with a massive infiltration of inflammatory cells. At days (F) 5, (G) 6, and (H) 7, edema and inflammatory cells were still present in the submucosa, whereas a healing process started in the epithelium. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 100×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 3 Time course of changes in colonic architecture after TNBS administration in PARS−/− mice. (A) Representative colonic sections from nontreated mice showed normal architecture (day 0). At days (B) 1, (C) 2, and (D) 3 after TNBS administration, a disruption of the structure occurred at the epithelium. At days (E) 4, (F) 5, (G) 6, and (H) 7, the mucosal and submucosal architecture appeared normal and/or typical of a healing process. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 100×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 4 Neutrophil infiltration and lipid peroxidation after TNBS-induced colitis is reduced in PARS−/− mice. (A) Myeloperoxidase, an enzyme present in neutrophils, was measured as an index of neutrophil infiltration into the injured tissue. Tissue myeloperoxidase activity was significantly enhanced in TNBS-treated PARS+/+ mice. In contrast, in TNBS-treated PARS−/− mice, the increase of myeloperoxidase was completely prevented compared with PARS+/+ animals (P < 0.001). (B) Malondialdehyde was augmented in tissue from wild-type mice with colitis, whereas it was prevented in tissues from TNBS-treated PARS−/− mice. Each data point is the mean ± SEM of 8 animals for each group. *Significantly different from TNBS-treated wild-type mice (P < 0.05). 2, PARS+/+; ■, PARS−/−. Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 5 Time course of nitrotyrosine formation after TNBS-induced colitis in PARS+/+ mice. (A) In colon sections from nontreated mice (day 0), no staining or nonspecific background for nitrotyrosine was found. (B) At day 1 after TNBS administration, a diffuse dark staining was localized mainly in the lumen surface of necrotic epithelium (C–G). Starting from day 2 up to day 6, staining for nitrotyrosine extended to mucosa, submucosa, and infiltrated inflammatory cells. (H) At day 7, nitrotyrosine staining was reduced in the area of a healing mucosa. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 100×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 6 Time course of nitrotyrosine formation after TNBS-induced colitis in PARS−/− mice. (A) In colon sections from nontreated mice (day 0), no staining or nonspecific background for nitrotyrosine was found. Nitrotyrosine staining was absent in the epithelial necrotic area at days (B) 1 and (C) 2, and (D–H) in the normal and healing mucosa at the following days up to day 7 after TNBS administration. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 100×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 7 Time course of ICAM-1 expression after TNBS-induced colitis in PARS+/+ mice. (A) Control tissues from nontreated animals showed a dark brown staining of the endothelium of blood vessels, indicating the presence of constitutive ICAM-1 protein (day 0). TNBS administration induced an increase of the positive staining for ICAM-1 along the endothelial vascular wall in the submucosa area, in the epithelial cells of the injured mucosa, and in infiltrated cells as early as (B) day 1 (C–G) up to day 6. (H) A representative microphotograph at day 7 shows persistence of ICAM-1 staining in infiltrated inflammatory cells in the healing mucosa. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 400×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 8 Time course of ICAM-1 expression after TNBS-induced colitis in PARS−/− mice. (A) Control tissues from nontreated animals showed a dark brown staining of the endothelium of blood vessels, indicating the presence of constitutive ICAM-1 protein (day 0). TNBS administration induced an increase of the positive staining for ICAM-1 at epithelial cells as early as days (B) 1 and (C) 2. (D–H) ICAM-1 staining was absent in the normal and healing mucosa at the following days up to day 7 after TNBS administration. Numbers indicate days after TNBS treatment. A similar pattern was seen in 5–6 different tissue sections in each experimental group (original magnification 400×). Gastroenterology 1999 116, 335-345DOI: (10.1016/S0016-5085(99)70130-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions