Search

Background: Sokeikakketsuto (SOK) is a Kampo medicine that can mitigate several types of pain, including arthralgia, neuralgia, low back pain, and myalgia, which may be introduced for the treatment of neuropathic pain in anti-cancer therapy. Considering that several Kampo medicines are known to have hepatoprotective and anti-inflammatory effects, we investigated the pharmacological mechanism of SOK in hepatocytes. Additionally, we examined another Kampo medicine, makyoyokukanto (MAK), as a reference as it has been reported to have similar efficacy for neuropathic pain. Methods: SOK or MAK was incubated with rat primary cultured hepatocytes treated with interleukin (IL)-1ß. The induction of inducible nitric oxide synthase (iNOS), nitric oxide (NO) production, iNOS signaling pathways, and the expression of other inflammatory mediators was investigated. ¥ Results: IL-1ß activated iNOS induction, followed by NO production. SOK and MAK reduced the expression of iNOS mRNA and its protein and decreased NO production. SOK and MAK also decreased the levels of tumor necrosis factor (TNF)-a and increased the levels of IL-6 and IL-1ß. Transfection experiments with iNOS promoter-luciferase constructs revealed that MAK reduced iNOS mRNA synthesis and stability; however, SOK only reduced mRNA synthesis. Both medicines suppressed the activation of nuclear factor (NF)-κB but did not block the upregulation of type I IL-1 receptor in two essential signaling pathways. Conclusions: SOK and MAK could prevent NO production by inhibiting iNOS gene expression, partly through NF-κB activation, in inflamed hepatocytes. [ABSTRACT FROM AUTHOR]

Background: The traditional medicine ipe is thought to have various pharmacological actions including anticancer and anti-inflammatory activities. However, there is little scientific evidence to demonstrate the organ-protective effects of ipe. The prevention of nitric oxide (NO) production in inflamed livers by inducible NO synthase (iNOS) is an indicator of liver protection. We examined proinflammatory cytokine-stimulated hepatocytes as a simple "in vitro liver injury model" to determine ipe's liver-protective effects of ipe and clarify its mechanisms. Methods: Primary cultured hepatocytes were treated with interleukin (IL)-1β in the presence or absence of ipe. The induction of iNOS and its signal pathway were analyzed. Results: Ipe inhibited the production of NO stimulated by IL-1β and showed the greatest effect (more than 90% inhibition) at 2 mg/ml. Ipe decreased iNOS protein and mRNA expression. Ipe decreased NF-κB activation (its translocation to the nucleus and DNA binding), although there was no effect on IκBα degradation. Ipe inhibited Akt activation, followed by decreased the type I IL-1 receptor mRNA and protein levels. Transfection experiments revealed that ipe decreased both activities of iNOS promoter transactivation and mRNA stability. In support of the latter observation, ipe inhibited the expression of the antisense transcript of the iNOS gene. Conclusion: Ipe blocked IκB kinase and phosphatidylinositol 3-kinase/Akt signal pathways, which caused the reduction of iNOS mRNA synthesis and its stability. This resulted in the inhibition of iNOS induction and NO production. Ipe may have a potent beneficial effect against NO-mediated injury in organs including the liver. [ABSTRACT FROM AUTHOR]

Background: Intracellular glutathione (GSH) plays an important regulatory role in the host response to liver injury. However, there have been few scientific reports on the anti-inflammatory effects of GSH. In the inflamed liver, proinflammatory cytokines stimulate liver cells, followed by expression of inducible nitric oxide synthase (iNOS). Excessive nitric oxide (NO) levels produced by iNOS are one of the factors involved in liver injury. Therefore, inhibiting iNOS induction is important for preventing liver injury. This study aimed to investigate the protective effects of GSH on the liver by examining interleukin (IL)-1ß-stimulated hepatocytes. Methods: Primary cultured rat hepatocytes were treated with IL-1ß in the presence or absence of GSH. Induction of iNOS and its signaling pathway were analyzed. Results: Addition of GSH decreased IL-1ß-induced iNOS protein and mRNA expression levels, which resulted in inhibition of NO production. GSH also decreased tumor necrosis factor (TNF)-a and IL-6 mRNA expression. GSH blocked "type I IL-1 receptor upregulation", one of the essential signaling pathways for iNOS induction, through inactivation of an upstream kinase, phosphatidylinositol 3-kinase/Akt. In contrast, GSH had no effects on degradation of IB and activation of NF-ĸB (nuclear translocation and its DNA binding). Transfection experiments revealed that GSH reduced iNOS mRNA levels at the promoter transactivation and mRNA stabilization steps. Delayed administration of GSH after IL-1ß addition also inhibited iNOS induction. Conclusions: Our study suggests that GSH affects induction of inflammatory mediators, including iNOS and TNF-a, indicating its therapeutic potential for organ injuries, especially for the liver. [ABSTRACT FROM AUTHOR]