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.

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.

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.

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.

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.

Effect of cyclosporine on liver regeneration in partial hepatectomized rats

PURPOSE: To evaluate the influence of the cyclosporine in liver regeneration in rats submitted to an experimental model of 70% hepatectomy. METHODS: Forty male rats were randomly divided in four subgroups (C.24h, C.7d, E.24h, E.7d), according to the drug used and the day of sacrifice (24 hours and 7 days). Cyclosporine (10mg/Kg/day) was given to the study subgroup and 1 ml of 0.9% sodium chloride was to the control subgroup. Resection of left lateral lobe and median lobe performing 70% of liver mass. During the animals' death, KWON formula was applied. Counting of mitotic figures and percentage of positive nucleus with PCNA and Ki-67 were evaluated. RESULTS: In the 2nd, 4th PO and death days, E.7d lose more weight than C.7d. Regarding to the KWON formula, the C.7d regenerated more than the C.24h and the same with the E.7d. Comparing between the groups, only E7d subgroup was statistically significant compared with C.7d, showing the stimulating effect of cyclosporine in liver regeneration. Immunohistochemestry had significant results between the study subgroups. The mitotic index revealed statistical differences in the control subgroups. CONCLUSION: Cyclosporine, in spite of being an immunosuppressive drug, has a positive effect in liver regeneration, although reduce the animal's body weight. .

Evaluation of liver regeneration with use of diet supplemented with l-arginine

PURPOSE: To compare controlled liver regeneration in rats submitted to 60% hepatic resection having L-arginine supplemented diet, based on weight changes of the regenerated liver, laboratory parameters of liver function and pathological findings. METHODS: Thirty-six rats were divided into two groups, control and L- arginine. The first received standard chow and saline solution by gavage. The second had supplementation with L- arginine. Animals were killed on postoperative period at 24h, 72h and seven days. For analysis of liver regeneration was used Kwon formula for weight, laboratory tests and mitosis. RESULTS: Weight, showed no benefit with L- arginine supplementation; however, intergroup comparison in the first 24h observed positive effect on supplementation (p=0.008). Alkaline phosphatase was increased in arginine group (p<0.04). The number of mitoses showed no difference between the two groups; however, in the first 24 hours, the supplemented group had higher number of mitoses within the groups (p=0.03). CONCLUSION: Supplementation with L-arginine did not show benefits in liver regeneration; however, supplemented group in the first 24 hours showed benefits over 72 hours and seven days of the evaluation by weight gain and number of mitosis. .

Glutamine and ornithine alpha-ketoglutarate supplementation on malate dehydrogenases expression in hepatectomized rats

PURPOSE: To evaluate the relative gene expression (RGE) of cytosolic (MDH1) and mitochondrial (MDH2) malate dehydrogenases enzymes in partially hepatectomized rats after glutamine (GLN) or ornithine alpha-ketoglutarate (OKG) suplementation. METHODS: One-hundred and eight male Wistar rats were randomly distributed into six groups (n=18): CCaL, GLNL and OKGL and fed calcium caseinate (CCa), GLN and OKG, 0.5g/Kg by gavage, 30 minutes before laparotomy. CCaH, GLNH and OKGH groups were likewise fed 30 minutes before 70% partial hepatectomy. Blood and liver samples were collected three, seven and 14 days after laparotomy/hepatectomy for quantification of MDH1/MDH2 enzymes using the real-time polymerase chain reaction (PCR) methodology. Relative enzymes expression was calculated by the 2-ΔΔC T method using the threshold cycle (CT) value for normalization. RESULTS: MDH1/MDH2 RGE was not different in hepatectomized rats treated with OKG compared to rats treated with CCa. However, MDH1/MDH2 RGE was greater on days 3 (321:1/26.48:1) and 7 (2.12:1/2.48:1) while MDH2 RGE was greater on day 14 (7.79:1) in hepatectomized rats treated with GLN compared to control animals. CONCLUSION: Glutamine has beneficial effects in liver regeneration in rats by promoting an up-regulation of the MDH1 and MDH2 relative gene expression. .

Sirolimus influence on hepatectomy-induced liver regeneration in rats / Efeito do sirolimo na regeneração hepática induzida por hepatectomia no rato

OBJECTIVE: To evaluate the influence of sirolimus on liver regeneration triggered by resection of 70% of the liver of adult rats. METHODS: we used 40 Wistar rats randomly divided into two groups (study and control), each group was divided into two equal subgroups according to the day of death (24 hours and seven days). Sirolimus was administered at a dose of 1mg/kg in the study group and the control group was given 1 ml of saline. The solutions were administered daily since three days before hepatectomy till the rats death to removal of the regenerated liver, conducted in 24 hours or 7 days after hepatectomy. Liver regeneration was measured by the KWON formula, by thenumber of mitotic figures (hematoxylin-eosin staining) and by the immunohistochemical markers PCNA and Ki-67. RESULTS: there was a statistically significant difference between the 24h and the 7d groups. When comparing the study and control groups in the same period, there was a statistically significant variation only for Ki-67, in which there were increased numbers of hepatocytes in cell multiplication in the 7d study group compared with the 7d control group (p = 0.04). CONCLUSION: there was no negative influence of sirolimus in liver regeneration and there was a positive partial effect at immunohistochemistry with Ki-67. .

OBJETIVO: avaliar a influência do sirolimo sobre a regeneração hepática desencadeada pela ressecção de 70% do fígado de ratos adultos. MÉTODOS: utilizaram-se 40 ratos Wistar que foram divididos aleatoriamente em dois grupos (estudo e controle), cada grupo foi subdividido em dois subgrupos iguais conforme o dia da morte (24 horas e sete dias). O sirolimo foi administrado na dose de 1mg/kg/dia no grupo de estudo e no grupo controle foi administrado 1ml de solução salina. As soluções foram administradas diariamente, desde três dias precedentes à hepatectomia até a morte dos ratos, para a retirada do fígado regenerado, realizada em 24h ou 7d após a hepatectomia. A análise da regeneração hepática foi mensurada pela fórmula de KWON, número de figuras de mitose pela técnica de hematoxilina-eosina e pelos marcadores imunoistoquímicos PCNA e Ki-67. RESULTADOS: demonstrou-se variação estatisticamente significativa quando comparado os grupos 24h com os grupos 7d através dos métodos de análise. Ao comparar os grupos de estudo e controle no mesmo período demonstrou-se variação estatisticamente significativa apenas pelo Ki-67 no qual foi verificado aumento do número de hepatócitos em multiplicação celular no grupo de estudo de 7d quando comparado com o grupo controle de 7d (p=0,04). . CONCLUSÃO: não demonstramos influência negativa do sirolimo na regeneração hepática e houve efeito parcial positivo pela análise imunoistoquímica utilizando Ki-67. .

Liver regeneration with l-glutamine supplemented diet: experimental study in rats / Avaliação da regeneração hepática com dieta suplementada com l-glutamina: estudo experimental em ratos

OBJECTIVE: To assess liver regeneration in rats after 60% hepatectomy with and without supplementation of L-glutamine through liver weight changes, laboratory parameters and histological study. METHODS: 36 male rats were divided into two groups: glutamine group and control group. Each group was subdivided into three subgroups, with death in 24h, 72h and seven days. The glutamine group received water and standard diet supplemented with L-glutamine, and the control recieved 0.9% saline. In all subgroups analysis of liver regeneration was made by the Kwon formula, study of liver function (AST, ALT, GGT, total bilirubin, indirect and indirect bilirubin and albumin) and analysis of cell mitosis by hematoxylin-eosin. RESULTS: In both groups there was liver regeneration by weight gain. Gamma-GT increased significantly in the control group (p < 0.05); albumin increased in the glutamine group. The other indicators of liver function showed no significant differences. Histological analysis at 72h showed a higher number of mitoses in the glutamine group, with no differences in other subgroups. CONCLUSION: Diet supplementation with L glutamine is beneficial for liver regeneration. .

OBJETIVO: Avaliar a regeneração hepática em ratos submetidos à hepatectomia de 60% com e sem suplementação de L-glutamina através de alteração ponderal do fígado, parâmetros laboratoriais e estudo histológico. MÉTODOS: Foram usados 36 ratos machos, distribuídos em dois grupos: grupo controle e grupo glutamina. Cada um foi subdividido em mais três subgrupos com óbito em 24h, 72h e sete dias. O grupo glutamina recebeu água e dieta padrão suplementada com L-glutamina e o controle solução fisiológica a 0,9%. Em todos os subgrupos foi feita análise da regeneração hepática através da fórmula de Kwon, estudo da função hepática (AST, ALT, gama GT, bilirrubina total, bilirrubina indireta e indireta e albumina) e análise de mitose celular pela coloração de Hematoxilina - Eosina. RESULTADOS: Nos dois grupos houve regeneração hepática pelo ganho ponderal. Gama GT aumentou significativamente no grupo controle (p<0,05) já albumina aumentou no da glutamina. Os demais indicadores da função hepática não apresentaram diferenças significantes. A análise histológica em 72h mostrou maior número de mitoses no grupo glutamina, não havendo diferença nos demais subgrupos. CONCLUSÃO: A suplementação de L-glutamina à dieta é benéfica para a regeneração hepática. .

Effects of bioflavonoid ternatin on liver regeneration and oxidative stress in rats

PURPOSE: To evaluate the effect of bioflavonoid ternatin (TRT) on rat liver regeneration and oxidative stress after 70% partial hepatectomy (PH). METHODS: Thirty six young male Wistar rats were randomly assigned to two groups of 18 animals each - control (G1) and experimental (G2) - and were submitted to PH under inhalatory diethylether anesthesia. G1 rats received daily intraperitoneal (ip) injections of saline (NaCl 0.9% solution) 0.1 mL/kg for 14 days; G2 animals received daily ip injections of TRT 0.1% 1.0mg/kg for 14 days. At 36h (T1), 168h (T2) and 336h (T3) post-PH timepoints, a subgroup of six rats in each group was chosen in a randomized way to complementary hepatectomy (CH) and blood samples haversting. Collected material was saved for laboratory analysis (total bilirubin (TB), D-Glucose, glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) and assessment of liver regeneration. RESULTS: TRT induced a significant decrease in liver and plasma GSH concentrations; liver regeneration process was not affected. TRT promoted a significant decrease in blood glucose levels 168h after partial hepatectomy compared with controls. TB levels remained unchanged. CONCLUSION: Intraperitoneal bioflavonoid ternatin injection in partially hepatectomized rats induces a decrease in oxidative stress and a significant hypoglycemic state, but does not promote any change in the evolution of liver regeneration.

Proliferative effect of aqueous extract of Hyptis fructicosa on liver regeneration after partial hepatectomy in rats / Efeito proliferativo do extrato aquoso da Hyptis fructicosa na regeneração hepática após hepatectomia parcial em ratos

PURPOSE: To evaluate the effect of aqueous extract of Hyptis fructicosa on hepatic regeneration after partial hepatectomy in rats. METHODS: Sixteen rats were divided in two groups: C (Control Group) and HF (Whose rats received aqueous extract of Hyptis fructicosa during 4 days using the dose of 100 mg/kg/day). On the consecutive day of this treatment, the animals of both groups underwent hepatectomy of about 67 percent of liver. Twenty four hours later, they were sacrificed, and the remaining mass of liver was removed and prepared to be studied through the PCNA immunohistochemical technique. RESULTS: The liver regeneration index of HF group was 53.56 ± 18.91 percent, while in C group was 21.12 ± 8.29 percent (p=0.0003). CONCLUSION: These results show that the administration of aqueous extract of Hyptis fructicosa using the dose of 100mg/kg/day increased the hepatocyte proliferation in the group HF.

OBJETIVO: Avaliar o efeito do extrato aquoso da Hyptis fructicosa sobre a regeneração hepática após hepatectomia parcial em ratos. MÉTODOS: Dezesseis ratos foram divididos em dois grupos: C (grupo controle) e HF (ratos que receberam o extrato aquoso da Hyptis fructicosa durante quatro dias na dose de 100mg/kg/dia). No dia consecutivo deste tratamento, os animais de ambos os grupos foram submetidos a hepatectomia de aproximadamente 67 por cento do fígado. Vinte e quatro horas depois, eles foram sacrificados, e que a massa restante do fígado foi retirado e preparado para ser estudado através da técnica de imuno-histoquímica PCNA. RESULTADOS: O índice de regeneração hepática do grupo HF foi 53,56 ± 18,91 por cento, enquanto no grupo C foi de 21,12 ± 8,29 por cento (p=0,0003). CONCLUSÃO: Estes resultados mostram que a administração do extrato aquoso da Hyptis fructicosa na dose de 100mg/kg/dia aumentou a proliferação de hepatócitos no grupo HF.

Efeitos dos ácidos graxos sobre a regeneração hepática em ratos / Effects of fatty acids on liver regeneration in rats

OBJETIVO: Estudar os efeitos dos ácidos graxos poli-insaturados (PUFA) ômega-3 e ômega-6 no estresse oxidativo e na regeneração hepática em ratos submetidos à hepatectomia parcial à 70 por cento (HP, hepatectomia a 70 por cento, hepatectomia parcial à Higgins-Anderson). MÉTODOS: 72 ratos Wistar machos jovens foram aleatoriamente distribuídos em quatro grupos de mesmo tamanho: controle, parcialmente hepatectomizados, e parcialmente hepatectomizados com aporte diário intraperitoneal, por duas semanas, de ou ômega-3 ou ômega-6. Nos tempos 36h (T1), 168h (T2) e 336h (T3) pós-HP, substâncias reativas ao ácido tiobarbitúrico (TBARS) e glutationa reduzida (GSH) foram medidos no plasma e no tecido hepático, enquanto glicose e bilirrubina total foram aquilatados no sangue. A massa do fígado residual, nos mesmos tempos, foi o parâmetro utilizado para estimar a evolução da regeneração hepática. RESULTADOS: PUFA ômega-3 inibiu a regeneração hepática e induziu redução na concentração de GSH hepático sete dias pós-HP. PUFA ômega-6, ao contrário, não mostrou efeito inibitório sobre a regeneração. Houve aumento da peroxidação lipídica tanto no sangue como no fígado com a administração de ômega-6. CONCLUSÃO: PUFA ômega-3 retardou a regeneração hepática pós-HP provavelmente por inibição do estresse oxidativo. PUFA ômega-6 aumentou as concentrações de TBARS no sangue e no fígado mas não alterou a evolução do processo regenerativo hepático.

OBJECTIVE: To study the effects of polyunsaturated fatty acids (PUFA) omega-3 and omega-6 in the oxidative stress and in liver regeneration in rats subjected to 70 percent partial hepatectomy (PH, 70 percent hepatectomy, Higgins- Anderson partial hepatectomy). METHODS: 72 young male Wistar rats were randomly divided into four equal-sized groups: control (G1), partially hepatectomized (G2), partially hepatectomized with two weeks daily intraperitoneal infusion of omega-3 (G3) and partially hepatectomized with two weeks daily intraperitoneal infuison of omega-6 (G4). In moments 36h (T1), 168h (T2) and 336h (T3) post-PH, thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) were measured in plasma and liver tissue, while glucose and total bilirubin were measured in blood. The mass of the residual liver in the same moments was the parameter used to estimate the evolution of liver regeneration. RESULTS: omega-3 PUFA inhibited liver regeneration and induced reduction of hepatic GSH concentration seven days post-PH. Omega-6 PUFA, in contrast, showed no inhibitory effect on regeneration. There was an increase of lipid peroxidation both in blood and liver with administration of omega-6. CONCLUSION: Omega-3 PUFA retarded post-PH liver regeneration, probably through inhibition of oxidative stress. Omega-6 PUFA increased TBARS concentrations in blood and liver but did not alter the evolution of the liver regenerative process.

Imunossupressão com tacrolimus favorece a regeneração hepática induzida por hepatectomia ampla em ratos / Tacrolimus-based immunossupression favours liver regeneration induced by extent hepatectomy in rats

OBJETIVO: Avaliar em dois momentos distintos da regeneração hepática a influência do Tacrolimus sobre o fenômeno da regeneração hepática desencadeada pela ressecção de 70 por cento do parênquima hepático em ratos plenamente desenvolvidos. MÉTODOS: Utilizaram-se 40 ratos Wistar com peso médio de 510,08 g ± 11.66 g distribuidos aleatoriamente em dois grupos de 20, cada grupo subdividido em dois subgrupos conforme o dia da morte após a hepatectomia. De acordo com o grupo os animais receberam por gavagem solução aquosa de Tacrolimus 0,1 mg/kg/dia ou solução salina no mesmo volume. Após três dias de pré-terapia todos foram submetidos à hepatectomia de 70 por cento pela ressecção dos lobos hepáticos mediano e lateral esquerdo que foram pesados para posterior cálculo da regeneração hepática pela fórmula de Kwon. Vinte e quatro horas ou sete dias após a hepatectomia, 10 animais de cada grupo foram mortos, os fígados remanescentes (regenerados) foram pesados e amostrados para realização de índice mitótico por hematoxilina-eosina e estudo imunoistoquímico com os marcadores PCNA e Ki-67. RESULTADOS: Os animais que receberam tacrolimus mostraram índice maior de regeneração hepática, atingindo significância estatística quando comparado ao subgrupo de animais mantidos com placebo quando analisados pelos parâmetros: fórmula de Kwon, índice mitótico e marcador PCNA. A tendência para o marcador Ki-67 foi idêntica aos outros parâmetros mas não alcançou significância estatística. CONCLUSÃO: A imunossupressão com tacrolimus possui efeito estimulatório no processo de regeneração hepática desencadeado pela hepatectomia 70 por cento em ratos Wistar adultos, plenamente desenvolvidos.

OBJECTIVE: To analyze, during two different moments of liver regeneration, the effect of the immunosuppressant Tacrolimus on the 70 percent hepatectomy model-induced liver regeneration in adult rats. METHODS: Forty Wistar adult rats, weighing 510.08 + 11.66 g were randomly divided into two groups, each group divided into two subgroups according to the death day after 70 percent hepatectomy . According to the group of study, rats received 0.1mg/Kg/day of Tacrolimus or the same volume of saline solution, by gavage. After three days of pre-therapy, all animals were submitted to 70 percent hepatectomy by resection of median and left lateral hepatic lobes which were weighed for posterior calculation of liver regeneration by Kwon´s formula. Twenty four hours or seven days after hepatectomy ten rats of each group were killed; the remaining liver (regenerated) was entirely resected, weighed and sampled for mitotic index on hematoxylin-eosin staining and immunohistochemical assays with PCNA and Ki-67 markers. Data were statistically analyzed by Mann-Whitney or Student "t" tests, with significance level of 5 percent (p<0.05). RESULTS: Rats receiving tacrolimus showed statistically significant higher levels of liver regeneration when compared to placebo according to Kwon's formula, mitotic index and PCNA marker. Identical trend was found with Ki-67 marker, but without statistical significance. CONCLUSION: Tacrolimus-based immunossuppression has stimulatory effect on liver regeneration process induced by 70 percent hepatectomy in adult Wistar rats.

Farnesol inhibits cell proliferation and induces apoptosis after partial hepatectomy in rats / Farnesol inibe a proliferação celular e induz a apoptose após a hepatectomia parcial em ratos

PURPOSE: To study farnesol (FOH) effects on liver regeneration after 70 percent partial hepatectomy (PH) in rats. METHODS: Animals received FOH (25 mg/100 g body weight/day) or corn oil (CO, 0.25 mL/100 g body weight/day, controls). After a 2 week-treatment, all animals were subjected to PH and euthanized at different time points (0 h, 0.5 h, 4 h, 8 h, 18 h and 24 h) after surgery. Hepatic cell proliferation (PCNA positive nuclei) and apoptosis (fluorescence microscopy) were evaluated. RESULTS: Compared to CO treatment, FOH treatment inhibited (p<0.05) cell proliferation at 24h (S phase of the cell cycle) after PH. This was preceded by an induction of apoptosis 0.5 h (p<0.05; G0/G1 transition phase) after surgery. CONCLUSION: The results of the present study suggest that apoptosis induction could be associated with the reduced number of cells at the S phase observed in FOH group. These novel in vivo data reinforce FOH as a promising chemopreventive and therapeutic agent against cancer.

OBJETIVO: Estudar o efeito do farnesol (FOH) durante a regeneração hepática em ratos submetidos à Hepatectomia Parcial (HP) a 70 por cento. MÉTODOS: Os animais foram tratados com FOH (25 mg/100g de peso corpórel/dia) ou óleo de milho (OM, 0,25 mL/100g de peso corpóreo/dia, grupo controle). Depois de 2 semanas de tratamento, todos os animais foram submetidos à HP e eutanaziados em diferentes momentos (0h, 30min., 4h, 8h, 18h, 24h.) após o procedimento cirúrgico. Foi avaliada a proliferação celular (imunohistoquímica para PCNA) e a apoptose (microscopia de fluorescência). RESULTADOS: Em comparação aos animais controles, animais tratados com FOH apresentaram menor (p<0,05) proliferação celular 24h. (fase S do ciclo celular) após a HP. Tal efeito foi precedido de uma indução de apoptose 30min. (p<0,05; transição entre as fases G0/G1 do ciclo celular) após a cirurgia. CONCLUSÃO: Os resultados do presente estudo sugerem que a indução da apoptose pode estar associada com o menor número de células na fase S observadas nos animais tratados com FOH. Essa nova evidência in vivo reforça o farnesol como um promissor agente preventivo e terapêutico contra o câncer.

The influence of estrogen on liver regeneration: an experimental study in rats / A influência do estrogênio na regeneração hepática: estudo experimental em ratos

PURPOSE: To recognize the regenerative capacity influenced by the administrating of estradiol. METHODS: 42 female Wistar rats were used, divided into two groups, the control and the experiment group. A resection of approximately 70 percent of the liver was made in the liver of these animals. The control group received an intramuscular injection of one ml of peanut oil. The experiment group were given estradiol hexahydrobenzoate (50µg) diluted in one ml of peanut oil. Calibrations were done after 36 hours and 7 days, using three methods: the formula of Kwon et al.21, to recognize gain in volume, counting of the mitosis figures in five fields and the percentage of positive PCNA nuclei. RESULTS: Gain in volume (mass) was similar in both groups after 36 hours (p=0.1873) and higher in the experiment groups after seven days (p=0.0447). Microscopy showed a similar number of mitosis figures after 36 hours (p=0.3528) and a tendency to be higher in the experiment group after 7 days (p=0.0883). The average of positive PCNA nuclei was higher in the experiment group both after 36 hours (p=0.0009) and 7 days (p=0.0000). CONCLUSION: The estradiol hexahydrobenzoate improved liver regeneration in rats submitted to a 70 percent hepatectomy.

OBJETIVO: Reconhecer a capacidade regenerativa influenciada pela administração de estradiol. MÉTODOS: Utilizaram-se 42 ratos Wistar, fêmeas, divididos em dois grupos controle e experimento. Realizou-se a ressecção de, aproximadamente, 70 por cento do fígado destes animais. Ratos do grupo controle receberam injeção intramuscular de um mililitro de óleo de amendoim, enquanto que os do grupo experimento receberam hexaidrobenzoato de estradiol (50µg) diluídos em um mililitro de óleo de amendoim. Fizeram-se as aferições com 36 horas e 7 dias, com 3 métodos: Fórmula de Kwon et al.21 para reconhecer ganho de volume, contagem das figuras de mitose existentes em 5 campos e percentual dos núcleos PCNA positivos em 5 campos. RESULTADOS: O ganho de volume (massa) foi semelhante nos dois grupos com 36 horas (p=0,1873) e maior no grupo experimento com 7 dias (p=0,0447). À microscopia observou-se número de figuras de mitose em número semelhante com 36 horas (p=0,3528) e tendência a ser maior no grupo experimento com 7 dias (p=0,0883). A média de núcleos PCNA positivos foi maior no grupo experimento tanto com 36 horas (p=0,0009) quanto com 7 dias (p=0,0000). CONCLUSÃO: O hexaidrobenzoato de estradiol favoreceu a regeneração hepática em ratos submetidos à hepatectomia 70 por cento.