The effects of nimesulide, a selective inhibitor of cyclooxygenase-2 (COX-2) on azoxymethane (AOM)-induced colon carcinogenesis were investigated in mice. AOM at a dose of 10 mg/kg body wt was administered to male ICR mice once a week for 6 weeks.
Disruption of myelin causes severe neurological diseases. An understanding of the mechanisms that control myelination and remyelination is needed to develop therapeutic strategies for demyelinating diseases such as multiple sclerosis (MS). Our previous finding indicating the critical involvement of the gamma chain of immunogloblin Fc receptors (FcRgamma) and Fyn signaling in oligodendrocyte differentiaion and myelination demands a fundamental revision of the strategies used for MS therapy, because antigen-antibody complexes in MS patients may induce the direct dysregulation of myelination process as well as the inflammatory destruction of myelin sheath. Here we show that the FcRgamma/Fyn signaling cascade is critically involved in cuprizone-induced demyelination/remyelination, with no lymphocytic response. The levels of phosphorylated myelin basic proteins (p-MBPs), especially the 21.5-kDa isoform, but not the levels of total MBPs, decreased markedly during demyelination induced by aging, cuprizone treatment, and double knockout of FcRgamma/Fyn genes. We also showed that the recovery from demyelination in cuprizone-treated and aged mice is achieved after administration of the herbal medicine Ninjin'yoeito, an effective therapy targeting the FcRgamma/Fyn-Rho (Rac1)-MAPK (P38 MAPK)-p-MBPs signaling cascade. These results suggest that the restoration of FcRgamma/Fyn signaling represents a new approach for the treatment of demyelinating diseases.
This study was conducted to obtain effective cancer chemopreventive agents with low toxicity from medicinal herbs. The effect of aqueous extracts from 9 medicinal herbs with antiinflammatory effect were examined on the formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF), putative preneoplastic lesions of the colon. Male F344 rats were treated with 15 mg/kg body weight of AOM once a week for two weeks. Herbal extract consisting of 2% of the diet was administered from 1 d prior to the first carcinogen treatment. The number of AOM-induced ACF per colon was counted at 4 week. Extracts of Coptidis Rhizoma and Scutellariae Radix significantly inhibited AOM-induced ACF formation. The number of ACF was decreased to 54% and 78% of that of the control by 2% Coptidis Rhizoma and Scutellariae Radix extract in the diet, respectively. Berberine and Baicalin, major ingredients of Coptidis Rhizoma and Scutellariae Radix, inhibited ACF formation at a dose equivalent to the amount in each herbal extract. Therefore, to investigate the mechanisms of action of berberine and baicalein which is the active substances of orally administered baicalin, their effects on cyclooxygenase 1 and 2 activities were studied. Berberine was found to inhibit cyclooxygenase 2 activity without inhibition of cyclooxygenase 1 activity, and baicalein inhibited cyclooxygenase 1 activity. Thus, Coptidis Rhizoma and Scutellariae Radix suppressed experimental colon carcinogenesis, and their chemopreventive effects were explained from the inhibition of berberine on cyclooxygenase 2 activity and baicalein on cyclooxygenase 1 activity.
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