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Lovastatin inhibits visceral allodynia and increased colonic permeability induced by lipopolysaccharide or repeated water avoidance stress in rats.
CC-BY-NC-NDStatins have been reported to block inflammatory somatic pain and have an anti-cytokine property. Lipopolysaccharide (LPS) or repeated water avoidance stress (WAS) induces visceral hypersensitivity and increases gut permeability in rats, which are mediated through proinflammatory cytokine-dependent pathways. Since visceral hypersensitivity with increased gut permeability plays a crucial role in the pathophysiology of irritable bowel syndrome (IBS), these above animal models are considered to simulate IBS. We hypothesized that lovastatin improves symptoms in the patients with IBS by attenuating these visceral changes. The threshold of visceromotor response (VMR) induced by colonic balloon distention was measured for the assessment of visceral sensation in rats. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue in colonic tissue for 15min using a spectrophotometer. Subcutaneously (s.c.) injected LPS (1mg/kg) reduced the threshold of VMR after 3h. Pretreatment with lovastatin (20mg/kg s.c. daily for 3 days) abolished this response by LPS. Repeated WAS (1h daily for 3 days) induced visceral allodynia, which was also blocked by repeated injection of lovastatin before each stress session. The antinociceptive effect of lovastatin on the LPS-induced allodynia was reversed by mevalonolactone, NG-nitro-L-arginine methyl ester or naloxone. Lovastatin also blocked the LPS- or repeated WAS-induced increased gut permeability. These results indicate the possibility that lovastatin can be useful for treating IBS
かぐらおか 第170号
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Prostaglandin I2 suppresses the development of diet-induced nonalcoholic steatohepatitis in mice.
Nonalcoholic steatohepatitis (NASH) is a hepatic manifestation of metabolic syndrome. Although the prostaglandin (PG)I2 receptor IP is expressed broadly in the liver, the role of PGI2-IP signaling in the development of NASH remains to be determined. Here, we investigated the role of the PGI2-IP system in the development of steatohepatitis using mice lacking the PGI2 receptor IP [IP-knockout (IP-KO) mice] and beraprost (BPS), a specific IP agonist. IP-KO and wild-type (WT) mice were fed a methionine- and choline-deficient diet (MCDD) for 2, 5, or 10 wk. BPS was administered orally to mice every day during the experimental periods. The effect of BPS on the expression of chemokine and inflammatory cytokines was examined also in cultured Kupffer cells. WT mice fed MCDD developed steatohepatitis at 10 wk. IP-KO mice developed steatohepatitis at 5 wk with augmented histologic derangements accompanied by increased hepatic monocyte chemoattractant protein-1 (MCP-1) and TNF-α concentrations. After 10 wk of MCDD, IP-KO mice had greater hepatic iron deposition with prominent oxidative stress, resulting in hepatocyte damage. In WT mice, BPS improved histologic and biochemical parameters of steatohepatitis, accompanied by reduced hepatic concentration of MCP-1 and TNF-α. Accordingly, BPS suppressed the LPS-stimulated Mcp-1 and Tnf-α mRNA expression in cultured Kupffer cells prepared from WT mice. PGI2-IP signaling plays a crucial role in the development and progression of steatohepatitis by modulating the inflammatory response, leading to augmented oxidative stress. We suggest that the PGI2-IP system is an attractive therapeutic target for treating patients with NASH.-Kumei, S., Yuhki, K.-I., Kojima, F., Kashiwagi, H., Imamichi, Y., Okumura, T., Narumiya, S., Ushikubi, F. Prostaglandin I2 suppresses the development of diet-induced nonalcoholic steatohepatitis in mice