Gastric toxicity of Alendronate and Methotrexate in Walker 256 carcinosarcoma jaw model / Toxicidade gástrica de Alendronato e Metotrexato em modelo de carcinossarcoma de Walker 256 em mandíbula

Introduction: Experimental animal models represent a key tool used to elucidate the mechanisms of action and toxicity of anticancer drugs. Objective: The purpose was to establish a correlation of neoplastic growth with the combinatorial therapeutic application of sodium alendronate (ALD) and methotrexate (MTX), and to evaluate the gastrointestinal toxicity of these drugs, in the rat Walker 256 carcinosarcoma inoculation model. Methods: Female rats were selected and randomly distributed into 5 groups (n=10): negative control (NC), positive control (PC), MTX-treated group, ALD-treated group, and MTX-ALD-treated group (MTX/ALD). Tumor cells were inoculated as a suspension of 1x106cells/mL into the alveolar cavities produced by exodontia procedures. The following parameters were evaluated: body weight, tumor volume and percentage of tumor inhibition, and gastrointestinal toxicity. Results: The body weight variation was statistically significant between NC animals and PC animals, and between NC animals and ALD-treated group (p<0.01). Tumor volume variation was statistically significant between PC animals, MTX-treated group and MTX/ALD-co-treated group (p<0.05). Analysis of gastric toxicity of MTX-treated group reveled slight reduction of chief (Ch) and parietal (Pr) cellular populations; ALD-treated group exhibited gastric mucosa without histological alterations of Ch cells but intense reduction of Pr cellular population; and MTX/ALD-co-treated group presented reduction of Ch and Pr cellular populations. Conclusions: ALD does not elicit significant antitumor effects on Walker 256 carcinosarcoma cells and decreases antitumor effects of MTX due to toxicity on the gastric epithelium, which is intensified with MTX association.

Introdução: Modelos experimentais em animais representam um instrumento fundamental para elucidar os mecanismos de ação e toxicidade de drogas anticâncer. Objetivo: estabelecer uma correlação do crescimento neoplásico com a aplicação terapêutica combinatória de alendronato de sódio (ALD) e metotrexato (MTX), e avaliar a toxicidade gastrointestinal dessas drogas, no modelo de inoculação de carcinossarcoma de Walker 256 em ratos. Métodos: Ratas fêmeas foram selecionadas e distribuídas aleatoriamente em 5 grupos (n = 10): controle negativo (NC), controle positivo (PC), grupo tratado com MTX, grupo tratado com ALD e grupo tratado com MTX-ALD (MTX/ALD). As células tumorais foram inoculadas como uma suspensão de 1x106 células/mL nas cavidades alveolares produzidas por procedimentos de exodontia. Os seguintes parâmetros foram avaliados: peso corporal, volume tumoral e porcentagem de inibição tumoral e toxicidade gastrointestinal. Resultados: A variação do peso corporal foi estatisticamente significante entre animais NC e animais PC, e entre animais NC e grupo tratado com ALD (p <0,01). A variação do volume tumoral foi estatisticamente significativa entre animais PC, grupo tratado com MTX e grupo tratado com MTX / ALD (p <0,05). A análise da toxicidade gástrica do grupo tratado com MTX revelou uma ligeira redução das populações celulares principais (Ch) e parietais (Pr); o grupo tratado com ALD exibiu mucosa gástrica sem alterações histológicas de células Ch mas intensa redução da população celular Pr; e o grupo tratado com MTX / ALD apresentou redução das populações celulares Ch e Pr. Conclusões: O ALD não provoca efeitos antitumorais significativos nas células do carcinossarcoma Walker 256 e diminui os efeitos antitumorais do MTX devido à toxicidade no epitélio gástrico, que é intensificada com a associação MTX.

Red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells / Própolis vermelha e L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256

ABSTRACT Objective: To evaluate the effect of red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells. Methods: The study consisted of two experiments with four groups each (total: 57 hamsters). In the experiment 1, the animals were inoculated with Walker tumor cells, followed by administration of test substances (red propolis 200mg/5mL/kg or L-lysine 150mg/kg) or control substances (gum arabic 5mL/kg or water 5mL/kg) for 10 days. The animals in the experiment 2 received red propolis, L-lysine, gum arabic or water at the same doses, for 33 days prior to inoculation of Walker tumor cells, followed by 10 days of treatment with the same substances. Based on single-plane images, angiogenesis was quantified (mean vascular area), in percentage, and tumor area (mm2) and perimeter (mm). Results: In the experiment 1, compared to animals receiving water, the mean vascular area expressed in percentage was significantly smaller in animal treated with propolis (p<0.05) and L-lysine (p<0.001). Conclusion: Both red propolis and L-lysine inhibited tumor angiogenesis in the new hamster cheek pouch model when administered after tumor inoculation.

RESUMO Objetivo: Avaliar o efeito da própolis vermelha e da L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256. Métodos: O estudo consistiu em dois experimentos com quatro grupos cada (total: 57 hamsters). No experimento 1, os animais foram inoculados com células de tumor de Walker, tendo em seguida administradas as substâncias teste (própolis vermelha 200mg/5mL/kg ou L-lisina 150mg/kg) ou controle (goma arábica 5mL/kg ou água 5mL/kg) por 10 dias. Os animais do experimento 2 receberam própolis vermelha, L-lisina, goma arábica ou água nas mesmas doses, por 33 dias antes do inóculo das células de tumor de Walker, seguido por 10 dias de tratamento com as mesmas substâncias. Baseado em imagens em plano único, foram quantificados a angiogênese (área vascular média), em termos percentuais, e a área (mm2) e o perímetro (mm) do tumor. Resultados: Comparada aos animais que receberam água, a área vascular média, expressa em percentagem, foi significativamente menor nos animais tratados com própolis (p<0,05) e com L-lisina (p<0,001). Conclusão: Tanto a própolis vermelha quanto a L-lisina inibiram a angiogênese no novo modelo de bolsa jugal de hamsters, quando administradas após a inoculação do tumor.

Walker-256 Tumor: Experimental Model, Implantation Sites and Number of Cells for Ascitic and Solid Tumor Development

Abstract The Walker-256 tumor is an important experimental model that allow the development of therapies as the biological behavior of this tumor is similar that occur in humans. In front of the above considerations, the aim of this study was to describe the experimental model of Walker-256 tumor, identify the implantations sites as well as define a usual quantity of tumoral cells to induce the ascitic and solid tumor, according to the specialized literature. Were selected 45 articles using the keyword "Walker-256 tumor", free available. Were possible to observe that 58% (n=26) of the studies inoculate the tumor cells in the animals flank 33% (n = 15) in the tibia bone, 7% (n = 3) in the femur and 2% (n = 1) in the paw. The major quantitates of cells used were 8 x 107 (20%), 1 x 105 (13%), 1 x 106 (11%) and 2 x 107 (11%). After that, the site commonly used to inoculate was the flank and quantitate still a controversy, being 1x105 and 8x107 the concentrations more used.

Antioxidant effects of açaí seed ( Euterpe oleracea ) in anorexia-cachexia syndrome induced by Walker-256 tumor

ABSTRACT PURPOSE: To assess antioxidant effects of açaí seed extract on anorexia-cachexia induced by Walker-256 tumor. METHODS: A population of 20 lab rats were distributed into four groups (n=5): Control Group (CG), which only received tumor inoculation. Experimental Group-100 (EG-100), with animals submitted to tumor inoculation and treated with seed extract in a 100 mg / ml concentration through gavage. Experimental Group-200 (EG-200), with animals submitted to tumor inoculation and treated with seed extract in a 200 mg / ml concentration. Placebo Group (GP), which received tumor inoculation and ethanol-water solution. We analyzed proteolysis, lipid peroxidation, tumor diameter and weight. RESULTS: Lipid peroxidation was representative only in the cerebral cortex, where there was more oxidative stress in rats treated with the extract (p = 0.0276). For proteolysis, there was less muscle damage in untreated rats (p = 0.0312). Only tumor diameter in treated rats was significantly lower (p = 0.0200) compared to untreated ones. CONCLUSIONS: The açaí seed extract showed no beneficial effect on the general framework of the cachectic syndrome in lab rats. However, some anticarcinogenic effects were observed in the tumor diameter and weight.

Influence of pneumoperitoneum on tumor implantation in parietal incision: a comparative study of trocar incision and laparotomy in rats

Videolaparoscopic surgery has enabled great progress in surgical procedures. However, the literature shows great controversy concerning its indication in oncological surgery for possibly increasing the implantation of metastases. This experimental study was carried out to help solve this controversy and analyze the influence of pneumoperitoneum as a cause of this implantation. A comparative study between incisions of trocars of videolaparoscopy and conventional laparotomy was conducted. For this analysis, 30 Wistar rats were divided into two equal groups: laparotomic group (A), that underwent a 5 cm laparotomy, which was left exposed for 15 minutes; and another (B), in which a 3 mmHg pneumoperitoneum was created with CO2 and two more trocars were inserted, maintaining the insufflation for the same period. In both groups, the tumor, Walker 256 carcinosarcoma, was inoculated in the surgical procedure. The evaluation was performed within the fifth and the seventh postoperative days. The result of the macroscopic evaluation indicated that the tumor invasion in group A reached 93.33% and the implantation in the laparoscopy incision reached 73.33%. Nevertheless, the histopathological exam showed tumor implantation in all incisions of both groups (100%). The study concluded that parietal tumor implantation is not influenced by pneumoperitoneum in incisions of trocars when compared with conventional laparotomy in rats. (AU)

A cirurgia videolaparoscópica proporcionou grande avanço nas técnicas cirúrgicas. No entanto, há controvérsia na literatura sobre sua indicação na cirurgia oncológica por possivelmente aumentar a implantação tumoral de metástases. No intuito de contribuir para esclarecer essa controvérsia, realizou-se este estudo experimental visando analisar a influência do pneumoperitônio como causa dessa implantação. Realizou-se um estudo comparativo entre incisões dos trocartes da videolaparoscopia e da laparotomia convencional. Para isso, foram utilizados 30 ratos Wistar divididos em dois grupos iguais: um laparotômico (A), que foi submetido à laparotomia com 5 cm de extensão, a qual ficou exposta por 15 minutos; e outro (B), no qual se efetuou pneumoperitônio de 3 mmHg com CO2 e colocaram-se mais dois trocartes, mantendo-se insuflado pelo mesmo período. Em ambos os grupos, inoculou-se o tumor no ato operatório, o carcinossarcoma 256 de Walker. A avaliação deu-se entre o quinto e sétimo dia de pós-operatório. Como resultado na avaliação macroscópica, há invasão tumoral no grupo A de 93,33% e implantação na incisão laparoscópica de 73,33%. No exame histopatológico, porém, revelou-se implantação tumoral em todas as incisões de ambos os grupos (100%). Conclui-se que a implantação tumoral não sofre influência do pneumoperitônio nas incisões dos trocartes comparadas com a laparotomia convencional em ratos. (AU)

Aitongxiao recipe regulated survivin and Bcl- 2 in rats' transplanted hepatoma carcinoma cell / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the main mechanisms of Aitongxiao Recipe (ATXR) for anti-tumor at the molecular level, and to clarify different efficient drugs' roles in anti-tumor, thus in-depth explaining the objectivity and substance of "cancer toxic" theory.</p><p><b>METHODS</b>Walker-256 tumor strain was used for Wistar rat transplanted liver cancer modeling. After successful modeling rats were randomly divided into 5 groups, i. e., the ATXP group, the qi regulating and blood circulating group (as the assembled I group), the heat clearing and detoxification group (as the assembled II group), the body resistance strengthening and cultivating group (as the assembled III group), and the model group, 10 in each group. Corresponding medication was given to rats in each group for 14 successive days. Finally rats were sacrificed and the tumor mass was taken out. The apoptosis rate and the cell cycle of tumor cells were detected by flow cytometry Annexin V/PI. The protein and mRNA expressions of Bcl-2 and survivin were detected using immunohistochemistry and real-time fluorescent quantitative PCR.</p><p><b>RESULTS</b>(1) The apoptosis of hepatoma carcinoma cells could be obviously promoted in the ATXP group. The cell cycle could also be affected, making major cells arrest at G0/G1 phase. The proliferation of hepatoma carcinoma cells was effectively prevented. The efficacy in the assembled II group was in line with that in the ATXP group with no statistical difference (P>0.05). It was also effective in the assembled III group, but its efficacy was not as good as that in the former two groups, showing statistical difference (P<0.01). (2) ATXP could obviously down-regulate the protein and mRNA expressions of Bcl-2 and survivin in hepatoma carcinoma cells. Drugs for heat clearing and detoxification showed significant effects on down-regulating the protein and mRNA expressions of Bcl-2 and survivin in hepatoma carcinoma cells. Their effects were similar to that of ATXP (P>0.05). The effects of drugs for body resistance strengthening and cultivating were not as good as the former two, showing statistical difference (P<0.01). Drugs for blood circulating and stasis removing could up-regulate the protein and mRNA expressions of Bcl-2 and survivin to some extent.</p><p><b>CONCLUSIONS</b>(1) ATXP could increase the apoptosis ratio of hepatoma carcinoma cells obviously through down-regulating the protein and mRNA expressions of Bcl-2 and survivin, thus inhibiting their proliferation. (2) Drugs for heat clearing and detoxification played the most important roles in ATXP. The evil heat and dampness (damp-heat insidious pathogen) is the most fundamental carcinogenic factors. The insufficiency of vital qi is also one of the pathogenic factors. The mechanisms of phlegm, stasis, and other pathological products are not clear and await further studies.</p>

Effects of Erbie San on Walker-256 liver cancer and adjustment to unbalance of VEGF/endostatin in rats / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the anticancer effects of Erbie San on the rats bearing Walker-256 liver cancer and the potential mechanism of its angiogenesis effects.</p><p><b>METHOD</b>Wistar rats bearing Walker-256 liver cancer were used in this study. The experimental groups were treated with Erbie San 1.25, 2.5, 5 g x kg(-1) x d(-1), and 5-Fluorouracil injection 75 mg x kg(-1), respectively. The tumor's weight, the expression of VEGF, Endostatin and the ratio of VEGF/endostatin in serum of each groups were observed.</p><p><b>RESULT</b>Compared to the model group, Erbie San 2.5, 5 g x kg(-1) x d (-1) and 5-Fluorouracil injection groups can reduce the tumor's weight significantly (P<0.05 or P<0.01). The expression of VEGF was reduced, while endostatin was increased, and the ratio of VEGF/endostatin was reduced (P<0.05 or P<0.01).</p><p><b>CONCLUSION</b>Erbie San can effectively inhibit the growth of Walker-256 liver cancer of rats and can inhibit the expression of VEGF but increase the expression of endostatin, which suggest that Erbie San has the inhibition of angiogenesis which is responsible for its anticancer effects.</p>

Effects of electroacupuncture on tumor growth and immune function in the Walker-256 model rat / 中国针灸

<p><b>OBJECTIVE</b>To study the effect of acupuncture on tumor and its mechanism.</p><p><b>METHODS</b>Liver cancer, gastric cancer and hypodermic tumor rat models were made by implantation of replicated Walker-256 cell strain. The 3 model rats were respectively divided into two groups at random, a model control group and an electroacupuncture group. The electroacupuncture groups were treated with electroacupuncture (EA) at "Zusanli" (ST 36), "Hegu" (LI 4) and "San-yinjiao" (SP 6), once each day, 15 min one session, for 15 days. The gross tumor volume and the tumor inhibitory rate, and the levels of humoral immunity index, including serum 1gG, IgM, IgA and C3, C4, and the levels of cellular immunity index, including CD4+, CD8+ and CD4+/CD8+ in the peripheral blood in each group were detected.</p><p><b>RESULTS</b>The gross tumor volumes in the EA groups were significantly smaller than those in the model control group (P<0.01). The contents of IgG, IgM and C3 in the EA groups increased significantly compared with those in the model control group (P<0.05 or P<0.01). The contents of IgA and C4 in the EA groups did not significantly change (P>0.05). The content of CD4+ and CD4+/CD8+ in the EA groups are significantly higher than those in the model control group (P<0.05 or P<0.01).</p><p><b>CONCLUSION</b>Acupuncture at "Zusanli" (ST 36), "Hegu" (LI 4) and "Sanyinjiao" (SP 6) can increase immune function and inhibit tumor growth in Walker-256 liver cancer, gastric cancer and hypodermic tumor rats.</p>

Effect of steep pulsed electric fields on the immune response of tumor-bearing Wistar mice / 生物医学工程学杂志

This study sought to evaluate the effect of steep pulsed electric fields (SPEFs) on the immune response of Wistar mice inoculated with Walker256 sarcoma. Thirty mice were randomly divided into three groups: control group (group A, inoculated with Walker256 sarcoma, not treated), treatment group (group B, inoculated with Walker256 sarcoma, treated by SPEFs), and normal control group (group C, inoculated with normal saline, not treated). Tumor size was measured before and every 3 days after treatment by vernier caliper. MTT methods were used to assess the lymphocytes proliferation and the natural killer (NK) cells activity. TNF-a activity was measured by ELISA. Statistical analysis was performed utilizing the SPSS10.0 software package. The experiment results revealed that tumor growth was significantly inhibited in group B as compared with group A (P < 0.01), and that lymphocytes proliferation, NK cells activity and TNF-a activity in group B were not significantly different from those in group C (P = 0.953, P = 0.130, P = 0.080, respectively) but markedly higher than those in group A (P < 0.05). The results also showed that SPEFs could not only kill tumor cells but also induce antitumor immune response and improve the immune function of the host efficiently.

An experimental study of energy controllable steep pulse in the treatment of rat with subcutaneous transplantive tumor / 生物医学工程学杂志

This experimental study was designed to investigate the effects and the expressions of microvessel density (MVD), vascular endothelial growth factor (VEGF) on the transplanted tumor in the rat model with Walker-256 after energy controllable steep pulse(ECSP). The experiment revealed that the steep pulse electrical field has better effect on tumor, compared with the control. The positive cell staining intensity of VEGF in the control group was significantly higher than that in ECSP group (P < 0.05). The number of MVD in the tumor tissues of ECSP group was significantly lower than that of tumor control group (P < 0.05). These results showed that ECSP could inhibit the growth and angiogenesis of tumor and its pathway is to down-regulate the expression of VEGF possibly.

Establishment of an rat model of tumor-associated depression / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish an animal model of tumor-associated depression and observe their biological behaviors and biochemical indices.</p><p><b>METHODS</b>Four groups of SD rats kept in separate cages were subjected to tumor cell inoculation with or without chronic unpredictable moderate stress administered before or after the inoculation. The depressive behaviors of the rats were examined by open-field test, and the concentration of 5-HT in the hippocampus was measured by spectrophotofluorometry. The body weight of the rats and volume of the implanted tumor were monitored and sugar water test was performed.</p><p><b>RESULTS</b>The rats subjected to chronic stress displayed significant depression, manifested by reduction in movement in the central area and total movement distance with prolonged resting time and shortened time of activity. These rats maintained high levels of depression even 12 days after withdrawal of chronic stress. Compared with the control group, the depressive rats showed obviously reduced sugar water consumption and hippocampal 5-HT level. Tumors of different sizes were observed in all rats in the 4 groups.</p><p><b>CONCLUSION</b>A rat model of tumor-associated depression is established, and the tumor-bearing rats exhibit obvious depressive behaviors and reduced level of neural substance (5-HT), which provides a good basis for studying the association of depression with tumorigenesis,progression and prognosis of tumor.</p>

Effect of chronic fish oil supplementation on renal function of normal and cachectic rats

In the present study we determined the effect of chronic diet supplementation with n-3 PUFA on renal function of healthy and cachectic subjects by providing fish oil (1 g/kg body weight) to female rats throughout pregnancy and lactation and then to their offspring post-weaning and examined its effect on renal function parameters during their adulthood. The animals were divided into four groups of 5-10 rats in each group: control, control supplemented with fish oil (P), cachectic Walker 256 tumor-bearing (W), and W supplemented with fish oil (WP). Food intake was significantly lower in the W group compared to control (12.66 ± 4.24 vs 25.30 ± 1.07 g/day). Treatment with fish oil significantly reversed this reduction (22.70 ± 2.94 g/day). Tumor growth rate was markedly reduced in the P group (16.41 ± 2.09 for WP vs 24.06 ± 2.64 g for W). WP group showed a significant increase in mean glomerular filtration rate compared to P and control (1.520 ± 0.214 ml min-1 kg body weight-1; P < 0.05). Tumor-bearing groups had low urine osmolality compared to control rats. The fractional sodium excretion decreased in the W group compared to control (0.43 ± 0.16 vs 2.99 ± 0.87 percent; P < 0.05), and partially recovered in the WP group (0.90 ± 0.20 percent). In summary, the chronic supplementation with fish oil used in this study increased the amount of fat in the diet by only 0.1 percent, but caused remarkable changes in tumor growth rate and cachexia, also showing a renoprotective function.

Quimioembolização transarterial hepática: modelo experimental de tumor em ratos / Transarterial hepatic chemoembolization: an experimental model in rats

OBJETIVO: Estabelecer um modelo de tumor no fígado de ratos para estudo do comportamento tumoral e avaliar o uso da quimiembolização transarterial. MÉTODOS: Utilizou-se oitenta e oito ratos Wistar, fêmeas, adultos, pesando entre 175- 284 g . Realizado incisão abdominal de 3 cm e implantou-se o carcinossarcoma de Walker 256 no lóbulo esquerdo do fígado. Dividiu-se em três grupos que receberam respectivamente 100x 10 , 200x 10 e 300x 10 células tumorais, avaliado a pega do tumor e a sobrevida. Em outro grupo de experimento com 39 animais inoculados com tumor de Walker foi avaliado a sobrevida dos animais após infusão do 5-Flourouracil (5-FU) por via intra-peritoneal e intra-arterial. RESULTADOS: O implante do carcinossarcoma de Walker no fígado de ratos apresentou desenvolvimento de 100 por cento, teve um crescimento rápido e desenvolvimento de metástases tardiamente, levando os animais ao óbito entre o sétimo e décimo quinto dia. A quimiembolização transarterial é possível de ser realizada experimentalmente. O uso do 5-FU aumentou a sobrevida em comparação ao grupo controle. CONCLUSAO: O modelo de implante do tumor de Walker no fígado de ratos é eficiente, de fácil reprodutibilidade, e sobrevida média de 9,96±0.3 dias. A quimioterapia transarterial hepática pode ser realizada experimentalmente para avaliar diversas drogas.

Modelo experimental de tumor na cavidade oral de ratos com carcinossarcoma de Walker 256 / Experimental model of Walker 256 carcinosarcoma developed in the oral cavity of rats

OBJETIVO: Estabelecer um modelo experimental de desenvolvimento tumoral na cavidade oral de ratos, permitindo, assim, o estudo da osteólise induzida pelo tumor nos ossos do complexo maxilomandibular como também nas estruturas dentais, através da caracterização histomorfológica da reabsorção óssea e dentária. MÉTODOS: Uma suspensão de células tumorais (0,1mL) do Carcinossarcoma de Walker 256, na concentração de 10(6) células/mL foi implantado na cavidade alveolar de ratos previamente aberta por exodontia. Os animais foram observados durante 12 (doze) dias consecutivos para determinação da curva de peso corpóreo, sendo posteriormente sacrificados e as mandíbulas removidas para exames radiográfico e histológico. RESULTADOS: No exame radiográfico foi verificada área lítica, sem evidência de reparo, na região dos alvéolos. No exame microscópico foi identificada infiltração óssea, periférica e central, de pequenas células hipercromáticas e pleomórficas, com leve infiltrado inflamatório mononuclear associado e áreas de necrose. O índice de pega foi de 100 por cento. CONCLUSAO: O modelo animal de invasão óssea, do tumor de Walker na cavidade oral, possibilita a avaliação in vivo de drogas antitumorais e esquemas terapêuticos no tratamento do câncer bucal.

Histopathological changes in rat transplanted hepatoma after lipiodol transarterial embolization / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the histopathological effect of hepatic arterial infusion of lipiodol on transplanted hepatoma in rats.</p><p><b>METHODS</b>Fourty-one rats bearing Walker-256 transplanted hepatoma were randomly divided into embolization group (n = 35, divided in 5 subgroups, with 7 rats in each) and control group (n = 6). Lipiodol (0.5 ml/kg)emulsified with 0.2 - 0.3 ml of 76% urografin (v:v = 1:1) was infused via gastroduodenal artery into hepatic artery in embolization group. Rats in the control group were given via the same route urografin only. Histopathological changes of the treated tumors were examined by light and transmission electron microscopy.</p><p><b>RESULTS</b>In the control rats treated with urografin alone, the average tumor size increased 2.8 fold on day 3, while that in the lipiodol treated rats increased 1.7 fold (P < 0.01). Compared with the control group, on day 3, 5, 10 after embolization treatment, tumor necrosis was more extensive (P < 0.01). In one of the treated rats, the tumor was completely necrotic on day 10. Inflammatory reaction was marked in the early post-embolic period, but it was replaced by fibrous tissue encapsulation. From day 1 on, in 17 of the 18 treated rats, apoptotic cells, identified by typical morphology under light and electronic microscopes, were observed, mainly in the tumor periphery.</p><p><b>CONCLUSION</b>In addition to cellular necrosis, apoptosis may be another important mechanism leading to cell death in hepatoma treated with transarterial embolization.</p>

A leucine-supplemented diet improved protein content of skeletal muscle in young tumor-bearing rats

Cancer cachexia induces host protein wastage but the mechanisms are poorly understood. Branched-chain amino acids play a regulatory role in the modulation of both protein synthesis and degradation in host tissues. Leucine, an important amino acid in skeletal muscle, is higher oxidized in tumor-bearing animals. A leucine-supplemented diet was used to analyze the effects of Walker 256 tumor growth on body composition in young weanling Wistar rats divided into two main dietary groups: normal diet (N, 18 percent protein) and leucine-rich diet (L, 15 percent protein plus 3 percent leucine), which were further subdivided into control (N or L) or tumor-bearing (W or LW) subgroups. After 12 days, the animals were sacrificed and their carcass analyzed. The tumor-bearing groups showed a decrease in body weight and fat content. Lean carcass mass was lower in the W and LW groups (W = 19.9 ± 0.6, LW = 23.1 ± 1.0 g vs N = 29.4 ± 1.3, L = 28.1 ± 1.9 g, P < 0.05). Tumor weight was similar in both tumor-bearing groups fed either diet. Western blot analysis showed that myosin protein content in gastrocnemius muscle was reduced in tumor-bearing animals (W = 0.234 ± 0.033 vs LW = 0.598 ± 0.036, N = 0.623 ± 0.062, L = 0.697 ± 0.065 arbitrary intensity, P < 0.05). Despite accelerated tumor growth, LW animals exhibited a smaller reduction in lean carcass mass and muscle myosin maintenance, suggesting that excess leucine in the diet could counteract, at least in part, the high host protein wasting in weanling tumor-bearing rats.

Decorin is one of the proteoglycans expressed in Walker 256 rat mammary carcinoma

Proteoglycan and glycosaminoglycan content was analyzed in a model of rat mammary carcinoma to study the roles of these compounds in tumorigenesis. Hyaluronic acid and proteoglycans bearing chondroitin and/or dermatan sulfate chains were detected in solid tumors obtained after subcutaneous inoculation of Walker 256 rat carcinoma cells. About 10 percent of sulfated glycosaminoglycan chains corresponded to heparan sulfate. The small leucine-rich proteoglycan, decorin, was identified as one of the proteoglycans, in addition to others of higher molecular weight, by cross-reaction with an antiserum raised against pig laryngeal decorin and by N-terminal amino acid sequencing. Decorin was separated from other proteoglycans by hydrophobic chromatography and its complete structure was determined. It has a molecular weight of about 85 kDa and a dermatan chain of 45 kDa with 4-sulfated disaccharides. After degradation of the glycosaminoglycan chain, three core proteins of different molecular weight (36, 46 and 56 kDa) were identified. The presence of hyaluronic acid and decorin has been reported in a variety of tumors and tumor cells. In the Walker 256 mammary carcinoma model, hyaluronic acid may play an important role in tumor progression, since it provides a more hydrated extracellular matrix. On the other hand, decorin, which is expressed by stromal cells, represents a host defense response to tumor growth

Changes in red blood cell osmotic fragility induced by total plasma and plasma fractions obtained from rats bearing progressive and regressive variants of the Walker 256 tumor

Two variants (A and B) of the widely employed Walker 256 rat tumor cells are known. When inoculated sc, the A variant produces solid, invasive, highly metastasizing tumors that cause severe systemic effects and death. We have obtained a regressive variant (AR) whose sc growth is slower, resulting in 70-80 percent regression followed by development of immunity against A and AR variants. Simultaneously with the beginning of tumor regression, a temporary anemia developed (about 8 days duration), accompanied by marked splenomegaly (about 300 percent) and changes in red blood cell osmotic fragility, with mean corpuscular fragility increasing from 4.1 to 6.5 g/l NaCl. The possibility was raised that plasma factors associated with the immune response induced these changes. In the present study, we identify and compare the osmotic fragility increasing activity of plasma fractions obtained from A and AR tumor bearers at different stages of tumor development. The results showed that by day 4 compounds precipitating in 60 percent (NH4)2SO4 and able to increase red blood cell osmotic fragility appeared in the plasma of A and AR tumor bearers. Later, these compounds disappeared from the plasma of A tumor bearers but slightly increased in the plasma of AR tumor bearers. Furthermore, by day 10, compounds precipitating between 60 and 80 percent (NH4)2SO4 and with similar effects appeared only in plasma of AR tumor bearers. The salt solubility, production kinetics and hemolytic activity of these compounds resemble those of the immunoglobulins. This, together with their preferential increase in rats bearing the AR variant, suggest their association with an immune response against this tumor

Modelo de tumor de pulmäo em rato com o carcinossarcoma de Walker / Lung tumor model in rat with Walker's carcinosarcoma

OBJETIVO: Desenvolver um modelo de tumor pulmonar em ratos com o carcinossarcoma de Walker e verificar in vivo a presença de tumor por meio de tomografia computadorizada (TC). MÉTODOS: Ratos Wistar fêmeas (n=47) foram anestesiados com pentobarbital, intubados por traqueostomia e submetidos a toracotomia para injeçäo no parênquima pulmonar de células do tumor de Walker ou do veículo das mesmas. O estudo consistiu de duas etapas: na primeira desenvolveu-se a técnica de implante do tumor e estabeleceu-se o número de células necessário para um bom índice de pega tumoral. Na segunda etapa, determinou-se o volume do tumor em cm3 (Dxd2/2) através de TC e necropsia (6º dia do implante), e analizou-se a sobrevida dos animais. RESULTADOS: O índice de pega do tumor foi 93,3 por cento, sendo 81,8 por cento na primeira etapa e 100 por cento na segunda. A mortalidade cirúrgica foi 17,0 por cento. As medidas dos tumores foram semelhantes (0,099 vs. 0,111 cm3) na tomografia e na necropsia, respectivamente (r=0,993; p<0,0001) e a sobrevida mediana foi 10 dias. CONCLUSAO: O alto índice de pega e a boa correlaçäo dos dados de tomografia com os de necropsia permitem, por meio deste modelo, o monitoramento tomográfico do crescimento tumoral e, portanto, a avaliaçäo da açäo in vivo de drogas anti-tumorais, além da análise de sobrevida sem a necessidade do sacrifício dos animais.

Modelo de tumor experimental em rim de ratos / Experimental tumor model in rats kidney

O carcinossarcoma 256 de Walker tem despertado o interesse de muitos pesquisadores como modelo experimental para estudo da biologia tumoral. OBJETIVO: estabelecer um modelo de tumor renal que possa ser usado para estudar in vivo e in vitro, as alteraçöes impostas pelas neoplasias. MÉTODOS: utilizados vinte ratos Wistar, machos, adultos, pesando entre 250-300 g, oriundos do Laboratório de Cirurgia Experimental da Universidade Federal do Ceará. Sob anestesia inalatória procedia-se uma pequena incisäo supraumbilical, e com manobra delicada fazia-se a exposiçäo do rim direito. Neste órgäo eram inoculadas 3x105 células tumorais viáveis. Os animais entäo eram mantidos em gaiolas individuais com as mesmas condiçöes ambientais e com água e dieta ad libitum. RESULTADOS: o Carcinossarcoma 256 de Walker, implantado no parênquima do rim direito de ratos Wistar apresentou índice de pega de 100 por cento, e crescimento rápido, invadiu por contiguidade as estruturas vizinhas, porém sem apresentar metástases, no entanto, levando os animais a óbito no curso médio de 14 dias. CONCLUSAO: o modelo de implante de tumor de Walker no parênquima do rim direito de ratos Wistar é eficiente, tem reprodutibilidade, apresentando um índice de pega de 100 por cento, e permitindo seu uso em linhas de pesquisa.