In order to examine the neurotoxic mechanism of oxygen radicals on cultured bovine oligodendrocytes, cytoxic effect of oxygen radicals was examined when cultures were treated with various concentrations of xanthine oxidase (XO) and hypoxanthine (HX) in culture medium. In addition, the neuroprotective effect of iron-chelators against the neurotoxicity induced by oxygen radicals was evaluated by MTT assay. Cell viability was remarkably decreased in a time-dependent manner after exposure of cultured bovine oligodendrocytes to 20mU/ml XO and 0.1mM HX for 4 hours. In the neuroprotective effect of iron-chelators on oxidant-induced neurotoxicity, tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) blocked the neurotoxicity induced by oxygen radicals, while DFX was not effective in blocking oxidant-induced neurotoxicity in these cultures. These results suggest that oxygen radicals are toxic in cultured bovine oligodendrocytes, and also selective iron-chelators such as TPEN are effective in blocking the neurotoxicity induced by oxygen radicals.
Allopurinol* ; Cell Survival ; Hypoxanthine ; Neuroprotective Agents ; Oligodendroglia ; Reactive Oxygen Species ; Xanthine Oxidase

Ultraviolet (UV) radiation is the main physiological stimulus for human skin pigmentation. Recently, nitric oxide (NO) have been involved in mediation of skin pigmentation induced by UVB. Rutin, a flavonoid of vegetables and fruits, has antiviral and antioxidant properties. Therefore, we investigated the effect of rutin on UVB-induced melano-genesis and NO production in HM3KO cells. In this study, we demonstrated that UVB-irradiation stimulated melanin content and tyrosinase activity in HM3KO cells. Rutin suppressed UVB-stimulated total melanin content and tyrosinase activity in a dose-dependent manner. Additionally, we showed that UVB-irradiation stimulated NO production in HM3KO cells. Rutin also suppressed UVB-induced NO production and repaired reduction of cell proliferation by UVB. UVB stimulation of melanogenesis was mimicked by exogenous NO donor (sodium nitroprusside, SNP), and rutin effectively suppressed it. Therefore, we concluded that rutin suppressed UVB-stimulated melanogenesis and that it is involved in melanogenesis regulation partially through the suppression of UVB-induced NO production.
Cell Proliferation ; Fruit ; Humans* ; Melanins ; Melanoma* ; Monophenol Monooxygenase ; Negotiating ; Nitric Oxide* ; Nitroprusside ; Rutin* ; Skin Pigmentation ; Tissue Donors ; Vegetables

Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi- odiopiperzine (ETP) metabolite called gliotoxin. Gliotoxin is an epidithiodiopiperzine compound which can both react with sulfhydryl groups and form hydrogen peroxide. The fungal toxin gliotoxin induces apoptotic cell death in a variety of cells. Apoptosis induced by gliotoxin need calcium but effect of calcium preconditioning is unknown by gliotoxin. We studied the effect of protein kinase C and calcium preconditioning on gliotoxin-induced apoptosis in H9c2 cell. PKC and calcium preconditiong inhibited DNA fragmentation by gliotoxin. From this above results suggest that gliotoxin induce apoptosis via caspase-3 activation, because caspase-3 inhibitor (DEVD-CHO) didn't induce apoptosis in gliotoxin treated H9c2 clls. Calcium and PKC preconditioning inhibit caspase-3 activation by gliotoxin. These data means that PKC preconditioning is related with caspase-3 regulate in gliotoxin-induced apoptosis.
Apoptosis* ; Aspergillus ; Calcium ; Caspase 3 ; Cell Death ; DNA Fragmentation ; Fungi ; Gliotoxin* ; Hydrogen Peroxide ; Protein Kinase C* ; Protein Kinases*

Nitric oxide (NO) can be either neuroprotective or neurotoxic, depending on the cell type from which it is released and the length and severity of the ischemic insult. In the present study, we investigated the neuroprotective effect of Seongpungtang, a Oriental traditional medicine, on ischemic brain insult by C(6) glial cells and microglia produced NO. O production was induced by lipopolysaccharide (LPS) only or LPS combined with phorbol-12-myristate-13-acetate (PMA) in C(6) glial cell and microglia, and we observed the suppressive effect of Seongpungtang on NO production increased by LPS only or LPS combined with PMA. The cells treated with the water extracts of Seongpungtang at 2 mg/ml does not change the viability. And the water extracts of Seongpungtang significantly suppress the NO production induced by LPS or LPS combined PMA in C(6) glial cells and microglia. To validate the neuroprotective effect of Seongpungtang by suppression of NO production, the microglial cells were treated with NF-kB inhibitor pyrrolidine dithiocarbamate (PDTC), and it is completely decreased the NO production induced by LPS combined with PMA. Moreover, the water extracts of Seongpungtang suppress morphological degeneration by LPS combined with PMA in C(6) glial cell and microglia. These results suggest that the protective effects of the water extracts of Seongpungtang against ischemic brain damages may be mediated by regulation of iNOS during ischemic condition.
Brain ; Ischemia ; Medicine, East Asian Traditional ; Microglia* ; Neuroglia* ; Neuroprotective Agents ; NF-kappa B ; Nitric Oxide* ; Water

Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.
Calcium Channels, L-Type ; Calcium Channels, T-Type ; Calcium* ; Cell Death ; Cytosol ; Diltiazem ; Down-Regulation ; Endoplasmic Reticulum ; Humans ; Myoblasts, Cardiac* ; NF-kappa B ; Nifedipine ; Nitric Oxide ; Nitroprusside ; S-Nitroso-N-Acetylpenicillamine ; Signal Transduction* ; Thapsigargin ; Tissue Donors

Nitric oxide (NO) is mainly involved in brain ischemic damage to elucidate the protective mechanism of NO pretreatment on ischemic-induced cytotoxicity. This study was investigated whether NO pretreatment inhibits the increase of iNOS expression by lipopolysaccharide (LPS) combined phorbol 12-myristate 13-acetate (PMA) via regulating NF-kB activation in C6 glial cells. C6 glial cells with LPS and PMA for 72 hours markedly induced NO, but sodium nitroprusside (SNP) (100 nM) pretreatment before exposure of LPS and PMA significantly supressed NO production, iNOS expression and NF-kB activation by LPS and PMA. In addition, LPS and PMA treatment for 72 hours induced severely cell death and LDH release from cell into media in C6 glial cells. However SNP pretreatment before treatment of LPS and PMA significantly protected LPS and PMA induced cytotoxicity. Treatment with LPS and PMA induced caspase 3 activation follewed by chromosomal condensation, and fragmentation of nuclei in C6 glial cells. SNP pretreatment before exposure to LPS and PMA supressed caspase 3 activation and inhibited chromosomal condensation and fragmentation of nuclei. From these above results, it is suggest that the protective effects of SNP pretreatment against LPS and PMA induced cytotoxicity may be mediated by inhibiting the expression of iNOS via regulating NF-kB activation.
Brain ; Caspase 3 ; Cell Death ; Neuroglia ; NF-kappa B ; Nitric Oxide* ; Nitroprusside