Anti-inflammatory effect of cannabinoid agonist WIN55, 212 on mouse experimental colitis is related to inhibition of p38MAPK.

AIM: To investigate the anti-inflammatory effect and the possible mechanisms of an agonist of cannabinoid (CB) receptors, WIN55-212-2 (WIN55), in mice with experimental colitis, so as to supply experimental evidence for its clinical use in future. METHODS: We established the colitis model in C57BL/6 mice by replacing the animals' water supply with 4% dextran sulfate sodium (DSS) for 7 consecutive days. A colitis scoring system was used to evaluate the severity of colon local lesion. The plasma levels of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and the myeloperoxidase (MPO) activity in colon tissue were measured. The expressions of cannabinoid receptors, claudin-1 protein, p38 mitogen-activated protein kinase (p38MAPK) and its phosphorylated form (p-p38) in colon tissue were determined by immunohistochemistry and Western blot. In addition, the effect of SB203580 (SB), an inhibitor of p38, was investigated in parallel experiments, and the data were compared with those from intervention groups of WIN55 and SB alone or used together. RESULTS: The results demonstrated that WIN55 or SB treatment alone or together improved the pathological changes in mice with DSS colitis, decreased the plasma levels of TNF-α, and IL-6, and MPO activity in colon. The enhanced expression of claudin-1 and the inhibited expression of p-p38 in colon tissues were found in the WIN55-treated group. Besides, the expression of CB1 and CB2 receptors was enhanced in the colon after the induction of DSS colitis, but reduced when p38MAPK was inhibited. CONCLUSION: These results confirmed the anti-inflammatory effect and protective role of WIN55 on the mice with experimental colitis, and revealed that this agent exercises its action at least partially by inhibiting p38MAPK. Furthermore, the results showed that SB203580, affected the expression of CB1 and CB2 receptors in the mouse colon, suggesting a close linkage and cross-talk between the p38MAPK signaling pathway and the endogenous CB system.

p38 MAPK inhibition alleviates experimental acute pancreatitis in mice.

BACKGROUND: The mitogen-activated protein kinases (MAPKs) signaling pathway is involved in inflammatory process. However, the mechanism is not clear. The present study was to investigate the role of p38 MAPK in acute pancreatitis in mice. METHODS: Mice were divided into 4 groups: saline control; acute pancreatitis induced with repeated injections of cerulein; control plus p38 MAPK inhibitor SB203580; and acute pancreatitis plus SB203580. The pancreatic histology, pancreatic enzymes, cytokines, myeloperoxidase activity, p38 MAPK and heat shock protein (HSP) 60 and 70 were evaluated. RESULTS: Repeated injections of cerulein resulted in acute pancreatitis in mice, accompanying with the activation of p38 MAPK and overexpression of HSP60 and HSP70 in the pancreatic tissues. Treatment with SB203580 significantly inhibited the activation of p38 MAPK, and furthermore, inhibited the expression of HSP60 and HSP70 in the pancreas, the inflammatory cytokines in the serum, and myeloperoxidase activity in the lung. CONCLUSION: The p38 MAPK signaling pathway is involved in the regulation of inflammatory response and the expression of HSP60 and HSP70 in acute pancreatitis.

The dual effect of cannabinoid receptor-1 deficiency on the murine postoperative ileus.

INTRODUCTION: Intestinal inflammatory responses play a critical role in the pathogenesis of postoperative ileus (POI). As cannabinoid receptor-1 (CB1) is involved in inhibiting gastrointestinal (GI) motility and anti-inflammation, we aimed to explore its contribution to POI. METHODS: Experimental POI was induced in adult female CB1-deficient (CB1-/-) mice and wild-type littermates (C57BL/6N) by standardized small bowel manipulation. Twenty-four hours after surgery, GI transit was assessed by charcoal transport. FITC avidin, F4/80, and myeloperoxidase immunohistochemistry techniques were used to evaluate the inflammatory response in the muscularis of ileum and colon. Expressions of p38MAPK and its phosphorylated form (pp38) in the intestine were determined. Plasma levels of proinflammatory cytokines and chemokines were measured by ELISA as well. RESULTS: POI was characterized by decreased GI transit (p<0.01) and accompanied by a marked intestinal and systematic inflammatory response in wild-type and CB1-/- mice. Increased numbers of inflammatory cells, including macrophages, neutrophils, and mast cells were observed in the muscularis of ileum and colon (p<0.01, or p<0.05). Plasma levels of interleukin-6 (IL-6), cytokine-induced neutrophil chemoattractant-1 (CINC-1/KC), and monocyte chemoattractant protein-1 (MCP-1) were elevated (p<0.01, or p<0.05). Expression of p38 and pp38 increased in the intestine (p<0.01, or p<0.05). CB1-/- mice showed an increased inflammatory response during POI, especially the systemic inflammatory markers, such as IL-6, KC, CINC1, and pp38 expression were increased as compared to those in WT mice (p<0.05). CONCLUSIONS: Intestinal motility was inhibited during POI. In this condition, inhibition of motility did not seem to be altered by the absence of CB1 receptors, however, an increased inflammatory response was observed in CB1-/- mice. Hence, CB1 receptor activation rather than inhibition may reduce the inflammatory response in POI, which has a remote potential to relate into reduced inhibition of intestinal motility during POI.

Cannabinoid HU210 protects isolated rat stomach against impairment caused by serum of rats with experimental acute pancreatitis.

Acute pancreatitis (AP), especially severe acute pancreatitis often causes extra-pancreatic complications, such as acute gastrointestinal mucosal lesion (AGML) which is accompanied by a considerably high mortality, yet the pathogenesis of AP-induced AGML is still not fully understood. In this report, we investigated the alterations of serum components and gastric endocrine and exocrine functions in rats with experimental acute pancreatitis, and studied the possible contributions of these alterations in the pathogenesis of AGML. In addition, we explored the intervention effects of cannabinoid receptor agonist HU210 and antagonist AM251 on isolated and serum-perfused rat stomach. Our results showed that the AGML occurred after 5 h of AP replication, and the body homeostasis was disturbed in AP rat, with increased levels of pancreatic enzymes, lipopolysaccharide (LPS), proinflammtory cytokines and chemokines in the blood, and an imbalance of the gastric secretion function. Perfusing the isolated rat stomach with the AP rat serum caused morphological changes in the stomach, accompanied with a significant increment of pepsin and [H+] release, and increased gastrin and decreased somatostatin secretion. HU210 reversed the AP-serum-induced rat pathological alterations, including the reversal of transformation of the gastric morphology to certain degree. The results from this study prove that the inflammatory responses and the imbalance of the gastric secretion during the development of AP are responsible for the pathogenesis of AGML, and suggest the therapeutic potential of HU210 for AGML associated with acute pancreatitis.

[Effect of angelicanaphtha on proliferation, apoptosis, collagen synthesis of human umbilical vein endothelial cells].

OBJECTIVE: To investigate the effects of angelicanaphtha on proliferation, cell cycle, apoptosis, and collagen synthesis of human umbilical vein endothelial cells (HUVEC). METHODS: HUVEC was cultured and passaged in Dulbecco's modified Eagle's medium (DMEM) and treated with angelicanaphtha 1 mg/ L, 4 mg/L, and 16 mg/L at 1, 3, 5, and 7 day respectively. The proliferation was measured with MTT method. The cell cycle and apoptosis were analyzed with flow cytometry and collagen synthesis was determined with radioimmunoassay. RESULTS: The proliferation of the HUVEC was accelerated by angelicanaphtha < or =4 mg/L and inhibited by angelicanaphtha at 16 mg/L (P < 0.05). Lower concentration (< or = 4 mg/L) of Angelicanaphtha decreased cells in G0/G1 phase and increased significantly cells in S phase and inhibited the apoptosis (P < 0.05). However, angelicanaphtha at 16 mg/L increased cells in G0/G1 phase and decreased cells in S phase and induced the apoptosis (P < 0.05). The collagen synthesis of HUVEC was inhibited by angelicanaphtha in concentration-dependent manner (P < 0.05 or 0.01). CONCLUSION: The proliferation effects of angelicanaphtha on HUVEC had dualistic regulation of increase by lower-concentration and inhibition by higher-concentration. Collagen synthesis of HUVEC was inhibited by angelicanaphtha in concentration-dependent manner.