Liver regeneration after extensive hepatectomy in rats: effect of preoperative chemotherapy with intravenous 5-fluorouracil

Purpose: To evaluate the effect of preoperative intravenous chemotherapy with 5-fluorouracil on liver regeneration in an experimental model of major hepatectomy in rats. Methods: Wistar rats were divided into two groups of 20 animals each and submitted to 70% hepatectomy 24 h after intravenous injection of 5-fluorouracil 20 mg/kg (fluorouracil group, FG) or 0.9% saline (control group, CG). After hepatectomy, each group was subdivided into two subgroups of 10 animals each according to the day of sacrifice (24 h or 7 days). Liver weight during regeneration, liver regeneration rate using Kwon formula, and the immunohistochemical markers proliferating cell nuclear antigen (PCNA) and Ki-67 were used to assess liver regeneration. Results: At early phase (24 h after hepatectomy) it was demonstrated the negative effect of 5-fluorouracil on liver regeneration when assessed by Kwon formula (p < 0.0001), PCNA analysis (p = 0.02). With regeneration process complete (7 days), it was possible to demonstrate the sustained impairment of chemotherapy with 5-fluorouracil on hepatocytes regeneration phenomenon when measured by Kwon formula (p = 0.009), PCNA analysis (p = 0.0001) and Ki-67 analysis (0.001). Conclusions: Preoperative chemotherapy with intravenous 5-fluorouracil negatively affected the mechanisms of liver regeneration after major hepatectomy in rats.

Effects of low-level laser therapy on liver regeneration and laser parameters employed / Efeitos da laserterapia de baixa potência na regeneração hepática e parâmetros empregados de laser

Low-level laser therapy has several biological effects; one of them is tissue regeneration. Recent studies have been held on the application of laser therapy on the liver of rats after partial hepatectomy to promote liver regeneration. The aim of this article was to review the recent studies on the effects of low-level laser therapy on rat liver regeneration after partial hepatectomy and the laser parameters used in those studies. A review of recent relevant literature was performed in Pubmed, Scielo, Medline, and Bireme databases. Articles related to the application of low-level laser therapy on hepatic regeneration were included. Articles with hepatic regeneration in the presence of pathologies were not included. Nine studies were found matching the study criteria. In most studies, low-level laser therapy promoted liver regeneration after partial hepatectomy, without further damage to the remaining liver. Not all laser parameters required for the reproducibility of the study were described by all authors. The therapeutic use of low-level laser therapy in liver regeneration can be promising; however, since the liver is a vital organ, and the laser application is intraoperative, future studies are necessary. The parameters used must be properly described and standardized to allow the reproducibility of the study, in order to define a therapeutic window and thus, consider its clinical use. It is also essential to clarify the mechanisms by which laser promotes liver regeneration to guarantee its safety and therapeutic efficacy.

Laserterapia de baixa potência tem vários efeitos biológicos, sendo um deles a regeneração de tecido. Sua aplicação no fígado de ratos após hepatectomia parcial para promoção de regeneração hepática tem sido estudada recentemente. O objetivo deste artigo foi revisar os estudos recentes dos efeitos da laserterapia de baixa potência na regeneração de fígado de ratos após hepatectomia parcial de fígado e os parâmetros de laser empregados. Uma revisão da literatura relevante recente foi realizada nas bases de dados Pubmed, Scielo, Medline e Bireme. Artigos sobre a aplicação da laserterapia de baixa potência na regeneração de fígado foram incluídos. Artigos sobre regeneração hepática na presença de patologias foram excluídos. Nove estudos foram encontrados correspondendo aos critérios do estudo. Na maioria dos estudos, a laserterapia de baixa potência promoveu regeneração hepática após hepatectomia parcial, sem causar danos adicionais ao fígado remanescente. Não foram descritos todos os parâmetros necessários para reprodutibilidade dos estudos por todos os autores. O uso terapêutico da laserterapia de baixa potência na regeneração de fígado pode ser promissor, entretanto, como o fígado é um órgão vital e a aplicação do laser é intraoperativa, estudos futuros são necessários, assim como os parâmetros da aplicação de laser precisam ser descritos apropriadamente e padronizados, para permitir a reprodutibilidade do estudo, para que uma janela terapêutica possa ser definida e seu uso clínico possa ser considerado. Também é essencial esclarecer através de quais mecanismos o laser promove regeneração de fígado para garantir sua segurança e eficácia terapêutica.

Acetylsalicylic acid (Aspirin®) and liver regeneration: experimental study in rats / Ácido acetilsalicílico (Aspirina®) e regeneração hepática: estudo experimental em ratos

ABSTRACT Objective: to evaluate the influence of acetylsalicylic acid (ASA) on cell proliferation after partial hepatectomy in rats. Methods: 40 male Wistar rats were separated into four groups of ten rats each. Groups 1 and 2 (controls): undergoing 30% partial hepatectomy and, after one day (group 1) and seven days (group 2), to euthanasia; daily administration of 0.9% saline solution (1mL per 200g of body weight). Groups 3 and 4 (experimental): undergoing 30% partial hepatectomy and, after one day (group 3) and seven days (group 4), to euthanasia; daily administration of ASA (40mg/mL, 1mL per 200g of body weight). The absolute number of cells stained with PCNA was counted in photomicrographs, in five fields, and it was calculated the mean of positive cells per animal and per group. Results: the final mean of PCNA+ cells per group was: in group 1, 17.57 ± 6.77; in group 2, 19.31 ± 5.30; in group 3, 27.46 ± 11.55; and, in group 4, 12.40 ± 5.23. There was no significant difference at the two evaluation times in the control group (p=0.491), but there was in the experimental group (p=0.020), with a lower number of PCNA+ cells on the seventh day. The comparison between the two groups, on the first day, showed more PCNA+ cells in the livers of the animals that received ASA (p=0.047), and on the seventh day the number was lower in the experimental group (p=0.007). Conclusion: ASA induced greater hepatocyte proliferation.

RESUMO Objetivo: avaliar a influência do ácido acetilsalicílico (AAS) na proliferação celular após hepatectomia parcial em ratos. Métodos: 40 ratos Wistar machos foram separados em quatro grupos com dez ratos cada. Grupos 1 e 2 (controles): submetidos à hepatectomia parcial de 30% e, após um (grupo 1) e sete dias (grupo 2), à eutanásia; administração diária de solução fisiológica 0,9% (1mL por 200g de peso). Grupos 3 e 4 (experimentos): submetidos à hepatectomia parcial de 30% e, após um (grupo 3) e sete dias (grupo 4), à eutanásia; administração diária de AAS (40mg/mL, 1mL por 200g de peso). Realizou-se a contagem do número absoluto de células coradas com PCNA em fotomicrografias, em cinco campos e cálculo da média de células positivas por animal e por grupo. Resultados: A média final de células PCNA+ por grupo foi: no grupo 1, de 17,57 ± 6,77; no grupo 2 de 19,31 ± 5,30; no grupo 3, de 27,46 ± 11,55; e, no grupo 4, de 12,40 ± 5,23. Não houve diferença significante nos dois tempos de avaliação no grupo controle (p=0,491), mas houve no grupo experimento (p=0,020), observando-se menor número de células PCNA+ no sétimo dia. A comparação entre os dois grupos, no primeiro dia, mostrou mais células PCNA+ nos fígados dos animais que receberam AAS (p=0,047), e no sétimo dia o número foi menor no grupo experimento (p=0,007). Conclusão: O AAS induziu maior proliferação hepatocitária.

Conservation of both hematocrit and liver regeneration in hepatectomies: a vascular occlusion approach in rats / Hepatectomia hemoconservadora no rato: preservação do hematócrito e da regeneração hepática

ABSTRACT Background: Hepatectomies promote considerable amount of blood loss and the need to administrate blood products, which are directly linked to higher morbimortality rates. The blood-conserving hepatectomy (BCH) is a modification of the selective vascular occlusion technique. It could be a surgical maneuver in order to avoid or to reduce the blood products utilization in the perioperative period. Aim: To evaluate in rats the BCH effects on the hematocrit (HT) variation, hemoglobin serum concentration (HB), and on liver regeneration. Methods: Twelve Wistar rats were divided into two groups: control (n=6) and intervention (n=6). The ones in the control group had their livers partially removed according to the Higgins and Anderson technique, while the rats in the treatment group were submitted to BCH technique. HT and HB levels were measured at day D0, D1 and D7. The rate between the liver and rat weights was calculated in D0 and D7. Liver regeneration was quantitatively and qualitatively evaluated. Results: The HT and HB levels were lower in the control group as of D1 onwards, reaching an 18% gap at D7 (p=0.01 and p=0.008, respectively); BCH resulted in the preservation of HT and HB levels to the intervention group rats. BCH did not alter liver regeneration in rats. Conclusion: The BCH led to beneficial effects over the postoperative HT and serum HB levels with no setbacks to liver regeneration. These data are the necessary proof of evidence for translational research into the surgical practice.

RESUMO Racional: As hepatectomias compreendem considerável perda sanguínea e utilização de hemoderivados, o que diretamente estão relacionados com maior morbimortalidade. A hepatectomia hemoconservadora (HH) é modificação da técnica de oclusão vascular seletiva em hepatectomia. Ela pode ser alternativa cirúrgica para evitar ou diminuir o uso de hemoderivados no perioperatório. Objetivo: Avaliar os efeitos da HH sobre o volume globular (VG), concentração de hemoglobina (HB) e sobre a regeneração hepática em ratos. Métodos: Dois grupos de ratos Wistar foram constituídos: controle (n=6) e intervenção (n=6). Os do grupo controle foram submetidos à hepatectomia parcial de Higgins e Anderson e os do grupo Intervenção à HH. VG e HB foram medidos nos dias D0, D1 e D7. A relação peso do fígado/peso do rato foi calculada em D0 e D7. A regeneração hepática foi analisada qualitativamente e quantitativamente. Resultados: Houve diminuição dos níveis de VG e HB nos ratos do grupo controle a partir de D1, atingindo decréscimo de 18% em D7 (p=0,01 e p=0,008 respectivamente); a HH permitiu a manutenção dos níveis de VG e HB nos ratos do grupo intervenção. A HH não alterou a regeneração hepática. Conclusão: HH resultou em níveis maiores de VG e HB pós-operatórios sem alterar a regeneração hepática. Pode-se considerar estes dados como a prova necessária para a translação à pesquisa clinicocirúrgica.

Assessment of remnant liver function and volume after selective ligation of portal vein and hepatic artery in a rat model

Abstract Purpose: To evaluate liver regeneration after selective ligation of portal vein and hepatic artery by 3D Computed Tomography in an experimental model. Methods: Sixteen Wistar rats were randomized into four equal groups: Group I- control (sham), Group II- isolated selective ligation of the hepatic artery, Group III- isolated selective ligation of the portal vein and Group IV- combined ligation of portal vein and hepatic artery. Before procedure and five days after a 3D CT Scan was performed to analyze the hypertrophy, weight and function of the remnant liver. Results: The largest regeneration rate and increase of weight in the hypertrophied lobe was detected in group IV, the first with an average of 3.99 (p=0.006) and the last varying from 6.10g to 9.64g (p=0.01). However, total liver weight and the R1 ratio (Hypertrophied Lobe Weight/Total Liver Weight) was higher in group III (P<0.001) when compared with groups I, II and IV and showed no difference between them. The immunohistochemical examination with PCNA also found higher percentages with statistical significance differences in rats of groups III and IV. It was possible to confirm a strong correlation between hypertrophied lobe weight and its imaging volumetric study. Liver function tests only showed a significant difference in serum gamma-glutamyltransferase and phosphorous. Conclusion: There is a largest liver regeneration after combined ligation of portal vein and hepatic artery and this evidence may improve the knowledge of surgical treatment of liver injuries, with a translational impact in anima nobile.

Consideraciones prácticas y fisiológicas de la regeneración hepática en el trasplante / Physiological and practical considerations on liver regeneration after liver transplantion

La regeneración hepática ha sido uno de los procesos más estudiados en la medicina al ser el hígado un órgano altamente importante y complejo del organismo, asiento de múltiples enfermedades y expuesto por su ubicación anatómica a los traumatismos. El trasplante hepático se ha convertido en uno de los procedimientos más frecuentes en la trasplantología de órganos, por lo que el conocimiento de los aspectos básicos de esta técnica terapéutica y el estudio de los mecanismos histológicos y fisiológicos vinculados con la regeneración hepática es fundamental para lograr un resultado satisfactorio. Se realizó un estudio exploratorio de la bibliografía vinculada con el tema, con el objetivo de exponer aspectos esenciales y actualizados vinculados a las modificaciones fisiológicas y la respuesta orgánica ante el trasplante hepático, además de algunas características clínicas prácticas en este procedimiento.

Liver regeneration has been the focus of intense study in medicine given the liver is a very important and complex organ, affected by multiple illnesses and vulnerable for injury due to its fixed position. Liver transplantation has become one of the most frequent transplantation procedures, thus, knowledge on the basic aspects of this therapeutic technique and the study of the histological and physiological mechanisms linked to liver regeneration is critical to achieve a satisfactory outcome. An exploratory research of the bibliography on this topic was conducted aiming to expose essential and updated aspects related to the physiological modifications and immune response after liver transplantation, and some practical clinical features of this procedure.

Pine ( Pinus densiflora ) needle extract could promote the expression of PCNA and Ki-67 after partial hepatectomy in rat

Abstract Purpose To investigate the effects of pine needle extract (PNE) on the expression of proliferating cell nuclear antigen (PCNA) and Ki-67 during liver regeneration induced by 70% partial hepatectomy (PH) in rat. Methods Forty-eight male rats (SD, 7 weeks) had surgery (70% PH). They were randomly divided into two groups. PH + PNE group was only provided PNE diluted in water (10%) for drinking and PH group was provided water from 5 days before surgery to the time of sacrifice. PNE was made by pressing and filtering. Animals were sacrificed at 12h, 24h, 36h, 60h, 84h, 168h after PH, respectively. The expressions of PCNA and Ki-67 were determined as proliferation indices. Results Immunohistochemistry turned out to increase the expression of PCNA and Ki-67. PCNA expression of PH+PNE group increased up to twice of that of PH group. Western blot also seemed to increase the PCNA expression. These results indicated the promotion of cell proliferation in liver tissue and hepatic regeneration. Conclusions Pine needle extract stimulates the expression of some mitotic proteins during liver regeneration induced by 70% PH in rats. It suggests that administration of pine needle extract could accelerate the liver regeneration after partial hepatectomy.

Multiple factors affect the regeneration of liver

SUMMARY OBJECTIVE To study factors affecting the liver regeneration after hepatectomy METHODS With 3D reconstitution technology, liver regeneration ability of 117 patients was analysed, and relative factors were studied. RESULTS There was no statistically difference between the volume of simulated liver resection and the actual liver resection. All livers had different degrees of regeneration after surgery. Age, gender and blood indicators had no impact on liver regeneration, while surgery time, intraoperative blood loss, blood flow blocking time and different ways of liver resection had a significant impact on liver regeneration; In addition, the patients' own pathological status, including, hepatitis and liver fibrosis all had a significant impact on liver regeneration. CONCLUSION 3D reconstitution model is a good model to calculate liver volume. Age, gender, blood indicators and biochemistry indicators have no impact on liver regeneration, but surgery indicators and patients' own pathological status have influence on liver regeneration.

RESUMO OBJETIVO Estudar os fatores que afetam a regeneração hepática após hepatectomia. MÉTODOS A capacidade de regeneração hepática de 117 pacientes foi analisada com a tecnologia de reconstituição 3D e foram estudados os fatores relacionados. RESULTADOS Não houve diferença estatística significante entre o volume de ressecção hepática simulada e a ressecção atual. Todos os fígados apresentaram diferentes graus de regeneração após cirurgia. Idade, gênero e indicadores sanguíneos não tiveram impacto na regeneração hepática, enquanto que tempo de cirurgia, perda sanguínea intraoperatória, tempo de bloqueio do fluxo sanguíneo e diferentes formas de ressecção mostraram impacto significante na regeneração do órgão. Além disso, condições patológicas dos pacientes, incluindo hepatite e fibrose hepática, tiveram impacto significante na regeneração hepática. CONCLUSÃO O modelo de reconstituição 3D é um bom modelo para calcular o volume do fígado. Idade, gênero, indicadores sanguíneos e bioquímicos não tiveram impacto na regeneração hepática, mas indicadores operatórios e condição patológica dos pacientes mostraram influência na regeneração do órgão.

Capsiate treatment in liver surgeries may compromise its recovery

Abstract Purpose: To investigate the effects of capsiate treatment on hepatic hyperplasia in partially hepatectomized rats. Methods: The animals were divided into a Capsiate group (CPH), a Capsiate Post-Partial Hepatectomy group (CPPH) and a Partial Hepatectomy Control group (PH). CPH and CPPH animals received 60 mg/kg/day Capsiate for 30 days. Next, the rats underwent partial hepatectomy. CPPH animals continued to receive treatment for 48 h after partial hepatectomy. Liver tissue and intracardiac blood samples were obtained 24 or 48 h after PH. Results: Capsiate treatment interfered with hepatic parameters, reducing the number of mitoses and apoptosis and increasing blood ALT and alkaline phosphatase concentrations. Conclusion: Capsiate treatment preceding hepatic surgery may compromise the initial period of postoperative recovery.

Effects of thymoquinone and curcumin on the regeneration of rat livers subject to 70% hepatectomy

Abstract Purpose: To investigate thymoquinone, curcumin and a combination of these two drugs were effective or not at the growth of liver. Methods: Forty female Wistar-Albino rats distributed into five groups of eight rats each, control, thymoquinone, curcumin, and thymoquinone/curcumin groups. Pathological specimens were studied using the Ki-67 Proliferation Index(PI); and arginase(Arg), tissue plasminogen activator(tPA), ceruloplasmin(Cer) and nitric oxide(NO) were studied in biochemical analysis. Results: Our results showed that Ki-67 proliferation index was low in Groups 1. The proliferation coefficient was significantly higher in the Group 2 and Group 4 than in the Group 1 and Group 3.(P < 0.001 between Groups 1 and 2, 1 and 4, and 3 and 4). There was no difference between Groups 2 and 4 (P = 1). The results of the biochemical Arg, tPA and Cer test showed statistically between the Group 1 and Group 2. NO showed significant differences Group 1 and 3. Conclusions: Thymoquinone and curcumin both have known positive effects on the organism. Histological and biochemical tests showed that thymoquinone is more effective than curcumin.

Influence of the colon in liver regeneration of rats submitted to hepatectomy and colectomy / Influência do cólon na regeneração do fígado de ratos submetidos à hepatectomia e colectomia

ABSTRACT Objective: to evaluate whether colectomy, associated with 70% hepatectomy, influences liver regeneration in rats. Methods: we distributed 18 Wistar rats in three groups of six animals each. In group I (sham), we performed laparotomy; In group II, colectomy + 70% hepatectomy; In group III, only 70% hepatectomy. On the 6th postoperative day, we collected blood by cardiac puncture under anesthesia, followed by euthanasia. We performed serum dosages of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin and alkaline phosphatase (AF), hepatocyte growth factor (HGF) and transforming growth factor-α (TGF-α). We calculated liver regeneration by the formula: liver weight ratio per 100g body weight at the time of euthanasia / liver weight preoperatively projected for 100g body weight × 100. Results: ALT and AST levels were significantly lower in group II when compared with group III (p<0.001). Albuminemia showed significantly higher levels in group II. Levels of HGF and TGF-α in group II were significantly higher than in group III. The percentage of hepatic regeneration was significantly higher in group II than in group III. Conclusion: Colectomy performed simultaneously with 70% hepatectomy had a positive influence on liver regeneration in rats. Further research is needed to reveal the molecular mechanisms of this effect and to characterize the colon influence in liver physiology.

RESUMO Objetivo: avaliar se a colectomia, associada à hepatectomia 70%, influencia a regeneração do fígado em ratos. Métodos: foram utilizados 18 ratos Wistar distribuídos em três grupos de seis animais cada. No grupo I (sham) foi realizada laparotomia; no grupo II colectomia + hepatectomia 70%; no grupo III apenas hepatectomia 70%. No sexto dia pós-operatório foi colhido sangue por punção cardíaca, sob anestesia, seguido de eutanásia. Foram realizadas dosagens séricas de aspartato aminotransferase (AST), alanina aminotransferase (ALT), albumina e fosfatase alcalina (FA), fator de crescimento de hepatócitos (HGF) e fator de crescimento transformador-α (TGF-α). A regeneração do fígado foi calculada pela fórmula: razão peso do fígado por 100g do peso corporal no momento da eutanásia/peso do fígado no pré-operatório projetado por 100g de peso corporal ×100. Resultados: Os níveis de ALT e AST foram significativamente menores no grupo II quando comparados com o grupo III (p<0,001). A albuminemia mostrou níveis significativamente mais elevados no grupo II. Os níveis de HGF e TGF-α no grupo II foram significativamente mais elevados que no grupo III. O percentual de regeneração hepática foi significativamente mais elevado no grupo II do que no grupo III. Conclusão: o estudo demonstrou que a colectomia realizada simultaneamente à hepatectomia 70% influenciou positivamente na regeneração do fígado em ratos. Pesquisas adicionais são necessárias para revelar os mecanismos moleculares deste efeito e para caracterizar a influência do cólon na fisiologia do fígado.

Does mesenchymal stem cell improve the liver regeneration after the 70% hepatectomy?

Abstract Purpose: To evaluate the effects of mesenchymal stem cells on liver regeneration in rats following a 70% hepatectomy. Methods: Forty rats were subjected to 70% hepatectomy and then ~106 mesenchymal stem cells (test group), or saline solution (control group), were infused into their livers via the portal vein. Each treatment group was divided into early and late subgroups (euthanized 3 d and 5 d following the operation, respectively). Group comparisons of Albumin, aminotransaminases (AST, ALT), and Alcaline Phosphatase (AP) levels, proliferative index (ki-67+ straining), and mitotic cell counts were conducted. Results: No significant differences in liver regeneration rate, number of mitoses, proliferative index, or serum levels of albumin, AST, or AP were observed. ALT levels were higher in the test group than in the control group (p<.05). Conclusions: Mesenchymal stem-cell therapy did not improve liver regeneration rate 3 d or 5 d after 70% hepatectomy in rats. Likewise, the therapy appeared not to affect liver function, proliferative index, or number of mitoses significantly.

Functional and cellular evaluation of the liver after low-power laser stimulation during surgery / Avaliação celular e funcional do fígado estimulada por laser de baixa potência no transoperatório

ABSTRACT Background: Partial hepatectomy is a surgical intervention of the liver that can trigger its regenerative process, where the residual lobes deflagrate a compensatory hyperplasia, causing its restoration almost to the original volume. Nevertheless, depending on the extent of liver damage its regeneration might be impaired. The low-power laser has been studied with beneficial results. Aim: To investigate the possible functional and mutagenic damage arising from the use of low-power laser used in liver regeneration after partial hepatectomy. Methods: Fifteen male adult Wistar rats were hepatectomizated in 70% and laser irradiated or not with dose of 70 J/cm2, 650 nm, 100 mW, directly on the remaining liver, during the perioperative period. These animals were divided into four groups: G1 (control, 7 days); G2 (laser, 7 days); G3 (control, 14 days); G4 (laser, 14 days). Were analyzed the liver weight; number of hepatocytes; deposition of collagen fibers; liver function tests: serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, bilirubin and micronucleus test in peripheral blood erythrocyte. Results: The liver weight was greater in G3 and G4 (p=0.001 and p=0.002) compared to other groups. The deposition of collagen fibers in G1 was statistically higher than the other groups (p=0.01). In tests of liver function and micronucleus test was not found significant differences between the studied groups. Conclusion: Low-power laser stimulation did not cause loss of liver function or mutagenic damage.

RESUMO Racional: A hepatectomia parcial é intervenção cirúrgica que pode desencadear processo regenerativo, onde os lobos residuais deflagram resposta de hiperplasia compensatória, ocasionando restauração próxima ao seu volume original. Contudo, dependendo da extensão das lesões hepáticas a regeneração pode ser prejudicada. O laser de baixa potência tem sido pesquisado com resultados benéficos no processo de regeneração hepática. Objetivo: Investigar os possíveis danos funcionais e mutagênicos decorrentes da utilização do laser de baixa potência utilizado na regeneração hepática após hepatectomia parcial. Métodos: Quinze ratos adultos Wistar foram hepatectomizados a 70%, irradiados ou não com laser, dose de 70 J/cm2, 650 nm,100 mW, de forma direta sobre o fígado remanescente, durante o período transoperatório. Os animais foram distribuídos em quatro grupos: G1 (controle, 7 dias); G2 (laser, 7 dias); G3 (controle 14 dias); G4 (laser,14 dias). Foram analisados o peso do fígado; número de hepatócitos; deposição de fibras colágenas; teste de função hepática: alanina aminotransferase, aspartato aminotransferase, fosfatase alcalina, gama glutamiltransferase, bilirrubinas e teste de micronúcleo em eritrócitos. Resultados: O peso do fígado apresentou-se aumentado nos grupos G3 e G4 (p=0,001 e p=0,002) comparados aos demais grupos. A deposição das fibras colágenas no G1 foi estatisticamente maior em relação aos demais grupos (p=0,01). Nos testes de função hepática e teste de micronúcleo não foram encontradas diferenças significativas entre os grupos. Conclusão: O laser de baixa potência não ocasionou perda de função hepática ou dano mutagênico.

Transection of the hepatic parenchyma associated or not with the contralateral portal vein branch ligature and its effect in liver regeneration / Efeito da transecção do parênquima hepático associada ou não à ligadura contralateral da veia porta na regeneração hepática

ABSTRACT Objective To analyze the influence of portal vein ligation in hepatic regeneration by immunohistochemical criteria. Methods Ten pigs divided into two groups of five animals underwent hepatectomy in two stages, and the groups were differentiated by ligation or not of the left portal vein tributary, which is responsible for vascularization of the left lateral and medial lobes of the pig liver. Five days after the procedure, the animals underwent liver biopsies for further analysis of histological and immunohistochemical with marker Ki67. Results The group submitted to hepatectomy with vascular ligation showed an increase of approximately 4% of hepatocytes in regeneration status, as well as a greater presence of Kupffer and inflammatory cells as compared to control. Conclusion As a result of positive cell replication observed through the Ki67 marker, we can suspect that the ligation of a tributary of the portal vein associated with liver resection promoted a greater stimulus of liver regeneration when compared to liver resection alone.

RESUMO Objetivo Analisar a influência da ligadura da tributária da veia porta no estímulo regenerativo hepático por meio de critérios imuno-histoquímicos. Métodos Dez suínos, divididos em dois grupos de cinco animais, foram submetidos à hepatectomia em dois estágios, sendo que os grupos foram diferenciados pela ligadura ou não da tributária da veia porta, responsável pela vascularização dos lobos lateral e medial esquerdos do fígado do suíno. Cinco dias após o procedimento, os animais foram reabordados para retirada de amostras hepáticas para posterior análise de histológica e imunoistoquímica com o marcador Ki67. Resultados O grupo submetido à hepatectomia com ligadura vascular apresentou incremento de 4% aproximadamente de hepatócitos em processo de regeneração, bem como grande número de células de Kupffer e células inflamatórias, quando comparado ao controle. Conclusão Em virtude da análise positiva da replicação celular observada por meio do marcador Ki67, pode-se observar que a ligadura de uma tributária da veia porta promoveu um maior estímulo de regeneração hepática, efeito observado com menor intensidade no grupo submetido apenas à ressecção hepática.

Propofol attenuates cytokine-mediated upregulation of expression of inducible nitric oxide synthase and apoptosis during regeneration post-partial hepatectomy

Abstract Purpose: To determine the effects of propofol and ketamine anesthesia on liver regeneration in rats after partial hepatectomy (PHT). Methods: Male Wistar albino rats were assigned randomly to four groups of 10. Anesthesia was induced and maintained with propofol in groups 1 and 2, and with ketamine in groups 3 and 4. PHT was undertaken in groups 1 and 3. Rats in groups 2 and 4 (control groups) underwent an identical surgical procedure, but without PHT. At postoperative day-5, rats were killed. Regenerated liver was removed, weighed, and evaluated (by immunohistochemical means) for expression of inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS), apoptosis protease-activating factor (APAF)-1, and proliferating cell nuclear antigen (PCNA). Also, blood samples were collected for measurement of levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6. Results: Between groups 2 and 4, there were no differences in tissue levels of iNOS, eNOS, and APAF-1 or plasma levels of TNF-α and IL-6. eNOS expression was similar in group 1 and group 3. Expression of iNOS and APAF-1 was mild-to-moderate in group 1, but significantly higher in group 3. Groups 1 and 3 showed an increase in PCNA expression, but expression in both groups was comparable. Plasma levels of TNF-α and IL-6 increased to a lesser degree in group 1 than in group 3. Conclusion: Propofol, as an anesthetic agent, may attenuate cytokine-mediated upregulation of iNOS expression and apoptosis in an animal model of liver regeneration after partial hepatectomy.

Células madre mesenquimales y medicina regenerativa en la cirrosis hepática / Mesenchymal stem cells and regenerative medicine in liver cirrhosis

Las células madre mesenquimales (MSCs) son células multipotentes con capacidad de auto-renovación, presentes en diferentes tejidos del organismo. En los últimos años se ha avanzado significativamente en su estudio debido a su potencial terapéutico en medicina regenerativa. Las MSCs se caracterizan por migrar selectivamente a sitios de injuria y remodelación y por su capacidad para evadir al sistema inmunitario y colaborar en la reparación tisular mediante la secreción de factores tróficos. Numerosos estudios pre-clínicos y clínicos analizan su potencial efecto terapéutico en la cirrosis hepática con resultados alentadores. Diversas evidencias experimentales sugieren que este efecto podría ser superior si se utilizaran MSCs como vehículo de genes terapéuticos. En este trabajo se revisa el rol de las MSCs en medicina regenerativa y su empleo en estudios clínicos y pre-clínicos, con énfasis en su potencial como vehículo de genes terapéuticos.

Mesenchymal stem cells (MSCs) are multipotent cells with self-renewal capacity which are present in diverse tissues. Recently, significant progresses have been made in the field of MSCs because of its therapeutic potential in regenerative medicine. MSCs selectively migrate toward sites of damage and remodeling, and have the ability to evade the immune system and to promote tissue repair through the production of a number of growth factors and cytokines. Many pre-clinical and clinical studies have been carried out to study its therapeutic effect in liver cirrhosis with promising results. In addition, experimental studies showed that this therapeutic effect can be improved by engineering MSCs to produce therapeutic genes. In this work, the role of MSCs in regenerative medicine and its clinical and pre-clinical applications are reviewed, with an emphasis on its potential as vehicles for therapeutic genes.

Effect of aqueous extract of the leaves of Baccharis trimera on the proliferation of hepatocytes after partial hepatectomy in rats

Abstract Purpose: To evaluate the effect of aqueous extract of Baccharis trimera leaves on the proliferative capacity of the liver after partial hepatectomy (PH) in rats. Methods: Twenty Wistar rats weighing between 300 and 450g were divided into two groups: control (HP) and test (HP100-rats that received the aqueous extract of Baccharis trimera for four days at a dose of 100 mg / kg / day). On the fifth day, animals from both groups underwent resection of 70% of the liver. Twenty-four hours later, they were sacrificed and the remnant liver was removed and prepared for studied through PCNA immunohistochemistry. Data analysis for comparison between the two groups was made through the non-parametric statistical test Mann-Whitney test. Results: In all the animals studied was found most abundant nuclear immunostaining positive hepatocytes interlobular located in regions of the liver. Quantitative analysis of PCNA-positive cells revealed positivity rate significantly higher mean (p = 0.02) in HP100 group (77.1 ± 13.6) compared to the HP group (45.8 ± 12.9). Conclusion: DAdministration of aqueous extract of the leaves of Baccharis trimera 100 mg/kg of animal has a significant positive effect on liver regeneration in rats, 24 hours after hepatectomy (70%).

Lycopene and resveratrol pretreatment did not interfere with the liver of hepatectomized rats

Abstract Purpose: To investigate the effects of lycopene and resveratrol pretreatment on hepatic hyperplasia in partially hepatectomized rats. Methods: The lycopene group and the resveratrol group received 40 mg/kg/day of lycopene or resveratrol, respectively (dissolved in olive oil or in saline solution, respectively) and administered via a gastric tube for 30 days. The partially hepatectomzed (PH) control groups received saline or olive oil via a gastric tube for 30 days, respectively, and the normal control group received no treatment. Liver tissue and intracardiac blood samples were obtained 24, 36 or 48 h after PH. Results: No areas of fibrosis were detected. No significant changes in mitotic index, in the number of apoptosis events or in aspartate aminotransferase and alanine aminotransferase levels were observed. Conclusions: Lycopene and resveratrol pretreatment did not interfere on hepatic hyperplasia in partially hepatectomized rats.

The effect of the aqueous extract Peumus boldus on the proliferation of hepatocytes and liver function in rats submitted to expanded hepatectomy

ABSTRACT PURPOSE: To assess the effect of aqueous extract of Peumus Boldus (AEPB) on the liver proliferative response after parcial hepatectomy of 70% (PH) in rodents. METHODS: Twenty Wistar rats were divided in two groups: AEPB100 (whose rats received 100mg/Kg of AEPB, once a day, orally, in 4 days prior to the first surgical procedure) and Vehicle (whose rats were treated similarly with distilled water). Both groups underwent PH. After 24 hours the remaining livers were removed for studying the proliferation of hepatocytes by Ki-67 and 2mL of blood were collected for serological assessment: cholesterol, glucose, triglycerides, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and total, direct and indirect bilirubin. All data were analyzed by Gaussian distribution. Statistically significant differences between mean values were analyzed using T Student's test. Non-Gaussian data were analyzed using Mann-Whitney's test. RESULTS: The liver of all these rats presented positive staining of Ki-67, indicating liver proliferation. Laboratory results showed no significant difference in serum values between the analyzed groups. The analysis of Ki-67 was significantly more positive in AEPB100 group than in Vehicle group. CONCLUSION: Aqueous extract of Peumus Boldus acute administration exerts significant positive effect on liver regeneration after 24h in rats that underwent parcial hepatectomy, while maintaining unchanged hepatic function.

Tranexamic acid action on liver regeneration after partial hepatectomy: experimental model in rats / Ação do ácido tranexâmico na regeneração hepática após hepatectomia parcial: modelo experimental em ratos

ABSTRACT Background: Different lesions may affect the liver resulting in harmful stimuli. Some therapeutic procedures to treat those injuries depend on liver regeneration to increase functional capacity of this organ. Aim: Evaluate the effects of tranexamic acid on liver regeneration after partial hepatectomy in rats. Method: 40 rats (Rattus norvegicus albinus, Rodentia mammalia) of Wistar-UP lineage were randomly divided into two groups named control (CT) and tranexamic acid (ATX), with 20 rats in each. Both groups were subdivided, according to liver regeneration time of 32 h or seven days after the rats had been operated. The organ regeneration was evaluated through weight and histology, stained with HE and PCNA. Results: The average animal weight of ATX and CT 7 days groups before surgery were 411.2 g and 432.7 g, and 371.3 g and 392.9 g after the regeneration time, respectively. The average number of mitotic cells stained with HE for the ATX and CT 7 days groups were 33.7 and 32.6 mitosis, and 14.5 and 14.9 for the ATX and CT 32 h groups, respectively. When stained with proliferating cell nuclear antigen, the numbers of mitotic cells counted were 849.7 for the ATX 7 days, 301.8 for the CT 7 days groups, 814.2 for the ATX 32 hand 848.1 for the CT 32 h groups. Conclusion: Tranexamic acid was effective in liver regeneration, but in longer period after partial hepatectomy.

RESUMO Racional: Muitas são as injúrias que acometem o fígado e levam a estímulo lesivo. Alguns procedimentos terapêuticos para tratamento dessas lesões dependem da regeneração hepática para aumentar a sua capacidade funcional. Objetivo: Avaliar o efeito do ácido tranexâmico na regeneração hepática após hepatectomia parcial em ratos. Método: Foram utilizados 40 ratos (Rattus norvegicus albinus, Rodentia mammalia) convencionais da linhagem Wistar-UP. Foram divididos aleatoriamente em dois grupos de 20: grupo controle (CT) e grupo ácido tranexâmico (ATX). Cada um deles foi divido em dois subgrupos para avaliar a regeneração hepática no tempo de 32 h e 7 dias do pós-operatório. A regeneração do órgão foi avaliada quanto ao peso e histologia, sendo esta última por hematoxilina-eosina e antígeno nuclear de proliferação celular. Resultados: A média dos pesos dos animais dos grupos ATX 7 dias e CT 7 dias no pré-operatório foram de 411,2 g e 432,7 g, respectivamente, e após a regeneração foram de 371,3 g e 392,9 g. As médias das taxas de mitose coradas por HE dos dois grupos em 7 dias foram de 33,7 e 32,6 mitoses, respectivamente, e de 14,5 e 14,9 mitoses para os grupos ATX e CT 32 h. A contagem de células por antígeno nuclear de proliferação celular mostrou valores de 849,7 para o grupo ATX 7 dias e 301,8 para o CT 7 dias; 814,2 para o grupo ATX 32 h e 848,1 para o CT 32 h. Conclusão: O ácido tranexâmico mostrou-se efetivo na regeneração hepática somente em período mais longo de observação após hepatectomia parcial.