• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.379-387
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• 2004

When an organism is exposed to various toxicants chronically, reactive oxygen species(ROS) are accumulated and eventually result in several biological effects from gene expression to cell death. In the present study we investigated the oxidative damage of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin(TCDD) and/or benzo(a)pyrene (B(a)P) in C100 cells. C100 cells treated with TCDD(30 nM) and B(a)P($3{\mu}M$) underwent diverse oxidative stress as determined through thiobarbituric acid-reactive substances(TBARS) formation, DNA fragmentation, DNA single strand break(SSB) assay, immunohistochemical staining of 8-hydroxy-2'-deoxyguanosine(8-OHdG), and mRNA expressions of antioxidant enzymatic genes such as Cu/Zn-SOD gene, GPx(glutathione peroxidase 5) gene, and catalase gene. Lipid peroxidation in C100 cells was determined through measuing the formation of TBARS. For theat, the cells were pretreated with TCDD(30 nM) and/or B(a)P($3{\mu}M$) for 0.5, 1, 2 and 4 days. TBARS formation was increased in TCDD(30 nM) and B(a)P($3{\mu}M$) and mixture($30nM\;TCDD+3{\mu}M\;B(a)P$) and positive control treatment groups comparing to the controls. Mixture treatment induced more DNA fragmentation than the single treatment group at day 6. Also, SSB in all treatment groups was clearly observed when compared with the negative control group. As with the expression of antioxidant enzyme, GPx 5mRNA, B(a)P alone and mixture($30nM\;TCDD+3{\mu}M\;B(a)P$) treatment were higher comparing to those of the negative control and TCDD treatment groups. Our results suggest that exposure of C100 cells to mixture of TCDD and B(a)P leads to significant oxidative damage comparing to the exposures to the individual chemicals. Mechanisms of action are discussed. Additional studies are needed to elucidate the detailed mechanism of mixture-induced toxicity.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.170-170
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• 1993

유전독성물절외 검출과 평가에 용이하게 사용할 수 있는 모델 시스템의 개발 및 DNA 회복기작을 규명할 목적으로 수종의 돌연변이, 발암원을 이용하여 배양 포유동물세포 및 어류세포에서 세포생존률, DNA 합성 및 복제억제의 양상 등을 비교 분석하였다. MMS및 MNNG 와 같은 알칼라제는 CHO 세포에서 유의한 DNA 합성저해, DNA 복재억제, DNA 단사절단 및 비주기성 DNA 합성률의 증가를 유발하였다. Benzo(a)pyrene과 3-methylcholanthrene좌 같은 DNA 상해 전구물질의 경우 유전독성 여부의 판정에는 반드시 S-9/15과 같은 대사활성계 또는 mouse embryonic fibroblast와 같은 대사 활성능이 있는 세포와의 co-culture system들이 필요함을 확인하였으며, 이들에 의한 DNA 상해와 복재억제 유도의 작용양상은 자외선의 작용양상과 유사하였다. 배양 어류세포에서 자외선에 의한 세포생존율의 측정, 광재활성능의 분석 및 자외선에 의해 유발된 피리미딘 이량체 절제능 검토 및 DNA 합성 저해능의 결과를 분석함으로써 유전독성 평가를 위한 모델 시스템 구축의 기초결과를 얻었다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.99-99
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• 1993

본 연구에서는 이미 benzo(a)pyrene유도 소핵시험에서 뚜렷하게 소핵생성억제능을 보인 polyhydroxy flavonol유도체중의 하나인 Galangin에 대하여 C57BL/6 mice를 이용하여 N-methyl-N'-nitro-N-nitrosoguanidine(이하 MNNG)에 의해 유도된 소핵생성빈도에 미치는 영향을 살펴보고, spleen lymphocyte 배양을 통해 bleomycin 및 MNNG유도 염색체이상에 미치는 영향과 MNNG에 의해 유발된 DNA adduts중 biomarker로서 7-methylguanine형성에 대한 Galangin의 영향을 살펴봄으로서 ,Galangin의 유전독성 억제효과 및 작용기전에 대한 연구를 하고자하며 향후 Galangin을 모핵으로하는 cancer chemopreventive agent로의 유도체 합성에 기여하고자 한다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.325-325
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• 1994

본 연구에서는 먼저 14종의 flavonoid화합물을 대상으로 발암물질로서 잘 알려져있는 benzo(a)pyrene[B(a)P]에 대한 소핵생성억제효과를 관찰하였다. 소핵시험을 이용한 유전독성억제실험에서 비적적 큰 활성을 보이는 flavonoid는 2,3 이중결합과 3,5,7-trihydroxyl기를 갖는 polyhydroxy flavonol화합물들이었다. 이중에서 galangin은 활성이 비교적 컸으며, 이같은 유전독성억제효과는 galangin투여시 B(a)P의 대사활성화가 감소되고 활성본태산물들의 DNA binding을 저해함으로서 나타났다. 한편, galangin은 대사활성화가 필요없는 1차 발암물질인 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)에 의한 소핵생성도 감소시켰다. 이러한 galangin의 alkylating agent에 대한 유전독성억제효과는 calf thymus DNA를 이용한 실험에서 DNA의 메칠화를 저해하는 기전으로 나타나는 것으로 판단되었다. galangin은 mitouycin과 같은 DNA cross-linking agent에 의한 소핵생성에도 억제효과를 나타내었다. 특히 동시투여(simultaneous treatment)나 사후투여(post-treatment)시보다 사전투여(pre-treatment)시에 소핵생성억제효과가 컸으며 사전연속투여(multiple Pre-treatment)시에는 낮은 용량에서도 효과가 컸다. 이러한 저용량의 사전연용투여에 의한 유전독성억제효과들은 B(a)P나 MNNG에 대해서도 잘 나타났다.

• Journal of Pharmacopuncture
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• v.16 no.3
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• pp.11-22
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• 2013

Objectives: The present investigation aimed at examining if post-cancer treatment with a potentized homeopathic drug, Condurango 30C, which is generally used to treat oesophageal cancer, could also show an ameliorating effect through apoptosis induction on lung cancer induced by benzo[a]pyrene (BaP) in white rats (Rattus norvegicus). Methods: Lung cancer was induced after four months by chronic feeding of BaP to rats through gavage at a dose of 50 mg/kg body weight for one month. After four months, the lung-cancer-bearing rats were treated with Condurango 30C for the next one ($5^{th}$), two ($5^{th}-6^{th}$) and three ($5^{th}-7^{th}$) months, respectively, and were sacrificed at the corresponding time-points. The ameliorating effect, if any, after Condurango 30C treatment for the various periods was evaluated by using protocols such as histology, scanning electron microscopy (SEM), annexinV-FITC/PI assay, flow cytometry of the apoptosis marker, DNA fragmentation, reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and western blot analyses of lung tissue samples. Results: Striking recovery of lung tissue to a near normal status was noticed after post-cancerous drug treatment, as evidenced by SEM and histology, especially after one and two months of drug treatment. Data from the annexinV-FITC/PI and DNA fragmentation assays revealed that Condurango 30C could induce apoptosis in cancer cells after post-cancer treatment. A critical analysis of signalling cascade, evidenced through a RT-PCR study, demonstrated up-regulation and down-regulation of different pro- and anti-apoptotic genes, respectively, related to a caspase-3-mediated apoptotic pathway, which was especially discernible after one-month and two-month drug treatments. Correspondingly, Western blot and immunohistochemistry studies confirmed the ameliorative potential of Condurango 30C by its ability to down-regulate the elevated epidermal growth factor receptor (EGFR) expression, a hallmark of lung cancer. Conclusion: The overall result validated a positive effect of Condurango 30C in ameliorating lung cancer through caspase-3-mediated apoptosis induction and EGFR down-regulation.

• Toxicological Research
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• v.20 no.3
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• pp.225-232
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• 2004

The suitability of the single cell gel electrophoresis (SCGE) assay as a test for the monitoring of genotoxicity of aquatic environment was evaluated. The SCGE assay was employed to detect DNA damage induced in clam (Spisula sachalinensis) exposed to a direct mutagen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or an indirect mutagen, benzo[a]pyrene (B[a]P). The cells of gill and digestive glands were isolated from clam by homogenization, which was the optimized cell dissociation method, and the level of DNA damage was assessed and expressed as mean tail length. In the gill cells, significant dose- and time-dependent increase was observed in the mean tail length at the concentration from 0.01 to 0.5 ppm MNNG for 96 h. The linear correlation between relative dam-age index (RDI) values was suggested to provide criteria of genotoxicity monitoring for direct acting mutagen. The dose- and time-dependent responses of the digestive glands cells were less sensitive than those of the gill cells. In contrast, the genotoxic response resulting from the exposure of 0.01～1.0 ppm B[a]P to clam revealed a higher sensitivity in the digestive glands cells than the gill cells. The comparison between the time profiles of genotoxic responses in clam and carp, the latter had been obtained in our previous study, indicated that the metabolism of genotoxic compounds in the two aquatic organisms were quite different each other. We conclude that the SCGE assay has the potential as a screening test for routine genotoxicity monitoring of aquatic organisms because of its higher sensitivity and simplicity.

• Natural Product Sciences
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• v.4 no.2
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• pp.105-114
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• 1998

The antimutagenic activity of a methanol extract of Ecklonia stolonifera (Laminariaceae) against aflatoxin $B_1\;(AFB_1)$ was demonstrated with the Salmonella typhimurium assay. The numbers of revertants per plate decreased significantly when this extract was added to the assay system using S. Salmonella typhimurium TA100. The methanol extract also exhibited significant inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and the DNA damage in mouse spleen lymphocytes induced by N-methyl-N-nitrosourea (MMU) and benzo(a)pyrene (B(a)P). The MeOH extract was then sequentially partitioned with $CH_2Cl_2,\;CH_2Cl_2$ insoluble intermediate, EtOAc, n-BuOH, and $H_2O$. All fractions possessed antimutagenic activity but the $H_2O$ fraction was inactive. Among active fractions, the EtOAc and $CH_2Cl_2$ insoluble intermediate fractions showed the highest activity. Column chromatography using $SiO_2$ and Sephadex LH-20 yielded phloroglucinol from the EtOAc fraction. Phloroglucinol also demonstrated significant antimutagenic activity, and inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and DNA damage in mouse spleen lymphocytes induced by MMU and B(a)P.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.159-159
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• 2003

Comet assay is a potential monitoring tool because DNA strand breakage may be produced by a wide range of agents. The comet assay, also called the single-cell gell electrophoresis (SCGE) assay, is rapid and sensitive method for the detection of DNA damage in cells. This study was performed for the identification of DNA damage in the cells from flounders and clams exposed to PAHs. As a control experiments, flounder and clam cells were exposed to $H_2O$$_2$. The cells exposed to $H_2O$$_2$ were displayed a typical nuclei movement DNA damage of cells were significantly increased when the isolated cells from the blood of flounders and the tissue of clams were in vitro exposed to the different concentrations (5, 10, 50, 100 ppb) of five kinds of PAHs (benzo[a]pyrene, pyrene, fluoranthene, anthrancene, and phenanthrene). For the in vivo test, flounders and clams were exposed to the different concentrations of BaP for 4 days. The results showed that DNA strand breakage was effected by the concentration of BaP and the duration of exposure. In high concentration of BaP, the mean tail lengths of nuclei was longer than it In low concentration, while the mean size of head DNA decreased. In this research, both in vitro and in vivo genotoxicity of PAHs could be biomonitored by the comet assay. Especially, clams and flounders seem to be useful as materials for monitoring genotoxic damage by comet assay.

• Environmental Mutagens and Carcinogens
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• v.10 no.1
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• pp.1-10
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• 1990

The regulation of DNA repair genes expression was investigated using fused genes, in which the promoter of repair genes was hybridized with the lacZ structural gene. The activities of beta-galactosidase expressed from the fused gense were highly increased when the host cells were exposed to methylating agents, such as methyl methansulfonate (MMS), N-methyl-N'-nitro-nitrosoguanidine (MNNG) and methyl nitrosourea (MNU). On the other hand, the enzyme activities from the fused genes were not induced when the cells were treated with ethylating or nonalkylating agents, such as ethyl methansulfonate (EMS), 4-nitroquinoline-1-oxide (4NQO), Bleomycin, and Benzo(a)pyrene (BP).

• Korean Journal of Acupuncture
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• v.18 no.1
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• pp.11-20
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• 2001

Cancer chemoprevention refer to the use of natural or synthetic substances to prevent the initiational and promtional events that occur during the process of carcinogenesis. The effect of Prunella Herba Vulgaris L. Aqua-acupuncture Solution (PVAS) and Prunella Herba Vulgaris L. Water-extracted Solution (PVWS) on the induction of phase II detoxification enzyme (quinone reductase, Glutathione S-transferase) and inhibition of phase I enzyme (cytochrome P4501A1) and benzo[a]pyrene-DNA adduct formation was examined. PVAS is potent inducers of quinone reductase activity. Glutathione levels were increased with PVAS, in cultured murine hepatoma Hepa1c1c7 cells. In addition glutathione S-transferase levels were increased with PVAS. However, there was 45.2% inhibition in the activity of cytochrome P4501A1 enzyme with the treatment of PVAS, $5{\times}$. At concentration of $1{\times}$ and $3{\times}$ of PVAS, the binding of $[^3H]B[a]P$ metabolites to DNA of NCTC-clone 1469 cell was inhibited by 25.3%, 45.0%, respectively. These results suggest that PVAS has chemopreventive potential by inducing quinone reductase and glutathione S-transferase activities, increasing GSH levels, inhibiting the activity of cytochrome P4501A1 and benzo[a]pyrene-DNA adduct formation.