N the normal controls in WT mice (P,0.05) and CB1??mice (P,0.01). TNF-a level remained unchanged among all experimental groups (Fig. 6D).p38MAPK Expression in Ileum and ColonRepresentative images and summarizing histograms for p38 and its phosphorylated form (pp38) in ileum of wild-type and CB1??mice were shown in Fig. 7. p38 expression is shown in Fig. 7A and 7C, and pp38 in Fig. 7B and 7D. It was noted that p38 and pp38 were lightly Dimethylenastron expressed in the mucosal epithelium and submucosa of ileum in normal or sham operated mice. During POI, p38 and pp38 expressions were significantly enhanced (P,0.01) and the expressions were particularly located in immune cells in the submucosal plexus and in smooth muscle layer (Fig. 7A and 7B). The enhancement of p38 and pp38 expression was even moreInflammation CB1 Receptor in Postoperative IleusFigure 8. p38MAPK expression in the colon of mice. A and C display images and histograms 16574785 for p38 in colon, and B and D for pp38 in colon of WT and CB1??mice. Data are given as mean6SEM (n = 4/group). *P,0.05, **P,0.01 vs.normal; ##P,0.01 vs.sham; and P,0.01 vs. the Cyproconazole web identically-treated groups in WT mice. Scale bar = 50 mm. doi:10.1371/journal.pone.0067427.gobvious in CB1??mice during POI compared to the corresponding WT group (P,0.01; Fig. 7C and D). Representative expression images and summarizing histograms for p38 and pp38 in colon of both kinds of mice are given in Fig. 8, as p38 expression is shown in Fig. 8A and 8C, and pp38 in Fig. 8B and 8D. Similar change patterns as that in the ileum were found. During POI, p38 and especially pp38 expressions were enhanced in both kinds of mice (P,0.01), with more significant increase in CB1??mice (P,0.05 for p38 or P,0.01 for pp38 vs. the corresponding WT groups(Fig. 8C and 8D).DiscussionPathogenesis of POI involves a number of factors, such as anesthesia, surgical access trauma, and intestinal manipulation, which lead to neuro-humoral dysregulation of GI motility [3?]. In late 1990 s, an inflammatory response was described during POI and subsequently confirmed by numerous reports [7,8]. At present, it is generally accepted that development of POI consists of two stages [10]. The first stage is the early postoperative period, within three hours after an abdominal operation, during which the spinal nerve pathway triggers nerve reflex inhibition of GI motility: spinal afferent nerve fibers are sensitized probably by events such as tissue damage, ischemia, or inflammation of potentially harmful mechanical/chemical stimuli resulting from surgery [27]. The second phase of POI seems to involve primarily the inflammatory response characterized by migration of leukocytes into theintestinal muscularis layer, and the release of pro-inflammatory cytokines, resulting in longer inhibition of GI motility. Specifically, POI is characterized by infiltration of leukocytes in the gut wall 24 h after surgery, and the majority of these cells are macrophages [7,10,28]. In this study, the method we used to induce postoperative ileus in mice is by mechanical intestinal manipulation which is an extremely well-established model world-wide [9,29,30]. However, it needs to be controlled by group size and standardized use under defined circumstances, to avoid the variability in experimental groups. In addition, we set up a time of 24 h after surgery as the point for investigation, considering that during this period the inflammation develops its full impact on inhibition of GI motility [28,31.N the normal controls in WT mice (P,0.05) and CB1??mice (P,0.01). TNF-a level remained unchanged among all experimental groups (Fig. 6D).p38MAPK Expression in Ileum and ColonRepresentative images and summarizing histograms for p38 and its phosphorylated form (pp38) in ileum of wild-type and CB1??mice were shown in Fig. 7. p38 expression is shown in Fig. 7A and 7C, and pp38 in Fig. 7B and 7D. It was noted that p38 and pp38 were lightly expressed in the mucosal epithelium and submucosa of ileum in normal or sham operated mice. During POI, p38 and pp38 expressions were significantly enhanced (P,0.01) and the expressions were particularly located in immune cells in the submucosal plexus and in smooth muscle layer (Fig. 7A and 7B). The enhancement of p38 and pp38 expression was even moreInflammation CB1 Receptor in Postoperative IleusFigure 8. p38MAPK expression in the colon of mice. A and C display images and histograms 16574785 for p38 in colon, and B and D for pp38 in colon of WT and CB1??mice. Data are given as mean6SEM (n = 4/group). *P,0.05, **P,0.01 vs.normal; ##P,0.01 vs.sham; and P,0.01 vs. the identically-treated groups in WT mice. Scale bar = 50 mm. doi:10.1371/journal.pone.0067427.gobvious in CB1??mice during POI compared to the corresponding WT group (P,0.01; Fig. 7C and D). Representative expression images and summarizing histograms for p38 and pp38 in colon of both kinds of mice are given in Fig. 8, as p38 expression is shown in Fig. 8A and 8C, and pp38 in Fig. 8B and 8D. Similar change patterns as that in the ileum were found. During POI, p38 and especially pp38 expressions were enhanced in both kinds of mice (P,0.01), with more significant increase in CB1??mice (P,0.05 for p38 or P,0.01 for pp38 vs. the corresponding WT groups(Fig. 8C and 8D).DiscussionPathogenesis of POI involves a number of factors, such as anesthesia, surgical access trauma, and intestinal manipulation, which lead to neuro-humoral dysregulation of GI motility [3?]. In late 1990 s, an inflammatory response was described during POI and subsequently confirmed by numerous reports [7,8]. At present, it is generally accepted that development of POI consists of two stages [10]. The first stage is the early postoperative period, within three hours after an abdominal operation, during which the spinal nerve pathway triggers nerve reflex inhibition of GI motility: spinal afferent nerve fibers are sensitized probably by events such as tissue damage, ischemia, or inflammation of potentially harmful mechanical/chemical stimuli resulting from surgery [27]. The second phase of POI seems to involve primarily the inflammatory response characterized by migration of leukocytes into theintestinal muscularis layer, and the release of pro-inflammatory cytokines, resulting in longer inhibition of GI motility. Specifically, POI is characterized by infiltration of leukocytes in the gut wall 24 h after surgery, and the majority of these cells are macrophages [7,10,28]. In this study, the method we used to induce postoperative ileus in mice is by mechanical intestinal manipulation which is an extremely well-established model world-wide [9,29,30]. However, it needs to be controlled by group size and standardized use under defined circumstances, to avoid the variability in experimental groups. In addition, we set up a time of 24 h after surgery as the point for investigation, considering that during this period the inflammation develops its full impact on inhibition of GI motility [28,31.
