• Toxicological Research
• /
• 제8권1호
• /
• pp.131-137
• /
• 1992

Sprague-Dawley rats aged six weeks divided into four groups and group 1, 2, 3 and 4 of rats were given an intrapertioneal injection of diethylnitrosamine at 200 mg/kg body weight. Group 4 was Control. Two weeks after beginning of the experiment, group 1 of rats were begun to feed on water containing 0.05% phenobarbital sodium as a promoter for six weeks, and CP-2 were intrapertioneally given to rats of group 2(20mg/kg) and group 3(1mg/kg). Three weeks after beginning of the experiment, partial hepatectomy was performed in all rats. Preneoplastic foci were identified histopathologically by glutathione S-transferase placental form (GST-P) activity. In the Immunohistochemical quantitative analysis of carcinogen-induced foci, it was concluded that CP-2 was not carcinogen.

• 대한수의학회지
• /
• 제29권1호
• /
• pp.45-50
• /
• 1989

홍삼 및 수삼이 랫트의 간조직에서 diethylnitrosamine(DEN)에 의해 유도되는 preneoplastic altered foci 형성에 미치는 영향을 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase (GST-P)-positive foci의 숫자는 DEN 단독투여군($9.07{\pm}5.69$)에 비하여 수삼병행 투여군 ($4.77{\pm}3.23$)에서, 면적은 DEN 단독투여군($0.93{\pm}0.65$)에 비하여 홍삼병행투여군 ($0.50{\pm}0.31$)에서 각각 현저한 감소를 나타냈다. 이러한 결과는 홍삼 및 수삼이 간암 발생을 억제하는 작용이 있음을 암시하였다.

• 대한수의학회지
• /
• 제32권4호
• /
• pp.649-661
• /
• 1992

This study was performed to compare DNA content by flow cytometer (FCM) and glutathione S-transferase placental form (GST-P) positive foci for searching objective and accurated properties of tumor. Sprague-Dawley rats aged six weeks were divided into three groups and group 1 and 2 of rats were given an intraperitoneal injection of diethylnitrosamine at 200mg/kg body weight and group 3 of rats were given saline. Three weeks after beginning of the experiment, all groups were performed partial hepatectomy. Group 1 of rats were begun to feed on diets containing 0.02% 2-acetylaminofluorene as a promoter for six weeks, group 2 and 3 of rats were begun to feed on basal diets. At 4, 6, and 8 weeks after initiation, all groups of rats were killed, livers were extracted for H & E stain, immunohistochemical stain, and DNA ploidy analysis. In quantitative analysis for GST-P positive lesion number and area by using Image Analyzer, group 1 and 2 represented significant difference in comparison with group 3. In ploidy distribution, diploid cells of group 1 and 2 were increased significantly in comparison with those of group 3 at 4, 6, and 8 weeks after initiation, respectively tetraploid cells were reduced. But S-phase cells were not changed significantly. It is concluded that ploidy change by FCM is useful as objective data for early detection in hepatocarcinogenesis. Therefore, methodology and study of DNA content are carried out for more objective and accurate ploidy analysis in liver tumor.

• Toxicological Research
• /
• 제27권4호
• /
• pp.247-251
• /
• 2011

To clarify whether inhibitory effect of estrogen on liver tumor is associated with cell proliferation, we investigated its role in diethylnitrosamine (DEN)-induced rat preneoplastic lesions, with time sequenced manners. F344 male rats (n = 90) were divided into three groups at 5 weeks of age. The mini-osmotic pumps providing a continuous infusion of DEN was implanted into the abdominal cavity of each animal in group 1, 2 and 3 at 6 weeks of age. To see the effect of estrogen, pellet containing 1 or 10 ${\mu}g$ of estradiol-3-benzoate (EB) was implanted subcutaneously in the animals of groups 2 or 3, respectively, one week prior to DEN treatment. Ten animals of each group were euthanized at 10, 14 and 18 weeks after DEN treatment. Liver tissues at each time point were fixed in 10% phosphate-buffered formalin and were processed and embedded in paraffin and 5 ${\mu}g$ sections mounted on a silanized slide. Glutathione S-transferase placental form (GST-P) positive foci and 5-bromo-2-deoxyuridine (BrdU) labeling cells were detected at each time point. Area of GST-P positive foci in DEN+EB 1 or 10 ${\mu}g$ group was significantly decreased compared to DEN alone at 14 weeks (p < 0.01 or p < 0.05, respectively) an at 18 weeks (p < 0.05 or p < 0.01, respectively). BrdU index in DEN+EB 1 or 10 ${\mu}g$ groups was significantly decreased compared to DEN alone at 14 weeks and at 18 weeks (p < 0.01). Taken together, we conclude that EB treatment decrease the DEN-induced liver preneoplastic lesions and this may be associated with decrease of cellular proliferation.

• 대한수의학회지
• /
• 제32권4호
• /
• pp.629-633
• /
• 1992

Caffeine이 랫드의 간조직에서 diethylnitrosamine(200mg/kg B.W., DEN)에 의해 유도되는 preneoplastic altered foci형성의 promotion단계에 미치는 효과를 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase(GST-P)-positive foci의 수는 caffeine 음수 $m{\ell}$당 2mg 병행투여군($3.10{\pm}2.74$) 및 1mg병행 투여군($5.86{\pm}2.83$) 모두에서 DEN 단독투여 대조군($11.55{\pm}5.82$)에 비하여 현저히 낮게 나타났으며 면적 또한 caffeine 2mg 병행투여군($0.13{\pm}0.11$), 1mg 병행투여군($0.21{\pm}0.12$)에서 DEN 단독투여 대조군($0.76{\pm}0.33$)에 비하여 유의성있는 낮은 수치가 관찰되었다. 간 세포배양에서 unscheduled DNA synthesis(UDS)는 DEN($250{\mu}g/m{\ell}$ of medium)단독처리군에 비하여 caffeine($200{\mu}g/m{\ell}$ of medium) 처리시 약 70% 감소하였다. 이러한 결과는 caffeine이 간암발생의 promotion단계에 작용하여 억제효과를 나타냄을 암시하며 이는 DNA회복의 억제와 관계됨을 알 수 있었다.

• 한국식품위생안전성학회지
• /
• 제6권1호
• /
• pp.13-26
• /
• 1991

간의 부분적 절제수술을 하지 않고 새로운 발암성 검색법을 찾고자, 화학물질에 민감한 신생암첫 Sprague-Dawley 랫드를 이용하여 diethylnitrosamine(DENA)으로 암을 유발시킨 후, 제1군에는 강력한 촉진제로서 2-acetylaminofluorene(2-AAF)을 사료하여 0.01%가 되게 섞어 투여하였고, 제2군은 약한 촉진제인 phenobarbital을 암수에 0.05% 농도로 녹여 토여하였으며, 제 3군은 대조군으로 DENA만을 1회 투여하였다. 그리고 발암성 평가는 glutathione S-transeferase placental form을 사용하여 검색하였다. 그 결과 체중에 대한 간의 무게비는 이유후 4주째 (7주)에 제2군이 제3군인 대조군에 비해 유의성 있게 (p<0.01)높았으며, 이유후 8주째(11주)에는 제1군과 제 2군이 대조군에 비해 각각 유의성 있게 (p<0.01, p<0.001)높았다. 그리고 이유후 4주(7주)째에 GST-P 양성병변을 이용한 전암병변의 면적을 비교해본바 제 1군과 제2군이 각각 유의성있게 (p<0.01, p<0.05)높게 나타났다. 이상의 결과에서 신생 랫드를 이용한 발암성 실험은 간의 부분적 절제수술을 하지 않고도 화학물질의 발암성을 좀더 이른 시기에 검색할 수 있음을 알 수 있었다. 그러므로 신생동물을 이용한 발암성 실험은 많은 화학물질들의 발암성을 검색하는데 매우 유용한 방법으로 사료된다.

• 대한수의학회지
• /
• 제31권3호
• /
• pp.337-342
• /
• 1991

Caffeine이 랫트의 간조직에서 diethylnitrosamine(200mg/kg B.W., DEN)에 의해 유도되는 preneoplastic altered foci형성의 initiation단계에 미치는 효과를 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase(GST-P)-positive foci의 수는 caffeine 음수수 ml 당 2mg병행투여군 $(7.48{\pm}3.33)$ 및 1mg 병행 투여군 $(7.50{\pm}3.32)$ 모두에서 DEN 단독투여대조군$(14.08{\pm}5.16)$에 비하여 현저히 낮게 나타났으며, 면적 또한 caffeine 2mg병행투여군 $(0.29{\pm}0.17)$, 1mg병행투여군 $(0.30{\pm}0.13)$에서 DEN단독투여대조군 $(0.46{\pm}0.21)$에 비하여 유의성 있는 낮은 수치가 관찰되었다. 이러한 결과는 caffeine이 간암발생의 initiation 단계에 작용하여 억제효과를 나타냄을 암시하였다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권5호
• /
• pp.2257-2261
• /
• 2012

Pinocembrin (5, 7-dihydroxyflavanone) is a flavanone extracted from the rhizome of Boesenbergia pandurata. Our previous studies demonstrated that pinocembrin had no toxicity or mutagenicity in rats. We here evaluated its effects on the initiation and promotion stages in diethylnitrosamine-induced rat hepatocarcinogenesis, using short- and medium-term carcinogenicity tests. Micronucleated hepatocytes and liver glutathione-S-transferase placental form foci were used as end point markers. Pinocembrin was neither mutagenic nor carcinogenic in rat liver, and neither inhibited nor prevented micronucleus formation as well as GST-P positive foci formation induced by diethylnitrosamine. Interestingly, pinocembrin slightly increased the number of GST-P positive foci when given prior to diethylnitrosamine injection.

• Environmental Analysis Health and Toxicology
• /
• 제13권3_4호
• /
• pp.71-75
• /
• 1998

Carbendazim, which is widely used fungicide, was investigated for rat hepatocarcinogenesis using a medium-term carcinogenicity bioassay. All rats were initially given a single dose (200mg/kg) of diethylnitrosamine (DEN) i.p. and then, starting 2 weeks later, carbendazim treatment group and positive control group received carbendazim (7 mg/kg/ day) and 2-acetylaminofluorene (2-AAF, 1%), respectively, in the diet for 6 weeks. All rats were subjected to two-thirds partial hepatectomy (PH) at week 3 and sacrificed at week 8. Carcinogenic potential was scored by comparing the number and area per cm$^2$ of induced glutathione-S-transferase placental form (GST-P) positive foci in the liver. Carbendazim had no effect in the increase of body weight, hematological and biochemical values, and the number and area of GST-P positive loci. These results suggest that this bioassay using DEN-PH method can be useful for detection of hepatocarcinogenic potentials of pesticide.

• Archives of Pharmacal Research
• /
• 제21권4호
• /
• pp.363-369
• /
• 1998

Glutathione S-transferase placental form (GST-P) positive foci development and its expression in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate (CF), and genotoxic carcinogen 2-amino-3-methylimidazo[4,5-f] quinoline (IQ) were investigated as a measure of carcinogenic potential of these chemicals. Male F344 rats were initially given a single intraperitioneal injection of diethyinitrosamine (200 mg/kg), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CF or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed at 8 weeks or 52 weeks, and liver tissues were examined for immunohistochemical staining of GST-P positive foci. The numbers (No./$cm^2$) and areas ($mm^2$/ $cm^2$) of GST-P positive foci were increased by IQ or PB, but were decreased by CF compare to the control. Consistent with the development of GST-P positive foci, a time-related increase in the expression of GST-P mRNA was found in the rats treated with IQ, whereas CF decreased it. The incidence of hepatocellular carcinoma at 52 weeks was increased by all three chemicals. These results show that PB and IQ induced GST-P positive foci, but the peroxisome proliferator CF did not, which suggest that the prediction of carcinogenic potency based on the development of prenoplastic foci may cause false negative in a particular category compounds like peroxisome proliferators.