Diet and liver apoptosis in rats: a particular metabolic pathway / La dieta y la apoptosis hepática en ratas: una ruta metabólica particular

Introduction: Various studies have indicated an association between modification in dietary macronutrient composition and liver apoptosis. Objective: To explain how changes in metabolic pathways associated with a high-protein, high-fat, and low-carbohydrate diet causes liver apoptosis. Methods: Two groups of rats were compared. An experimental diet group (n = 8) using a high-protein (59.46%), high-fat (31.77%), and low-carbohydrate (8.77%) diet versus a control one (n = 9) with American Institute of Nutrition (AIN)-93-M diet. Animals were sacrifi ced after eight weeks, the adipose tissue weighed, the liver removed for fl ow cytometry analysis, and blood collected to measure glucose, insulin, glucagon, IL-6, TNF, triglycerides, malondialdehyde, and β-hydroxybutyrate. Statistical analysis was carried out using the unpaired and parametric Student’s t-test and Pearson’s correlation coefficients. Significance was set at p < 0.05. Results: Animals from the experimental group presented less adipose tissue than dose of the control group. Percentage of nonviable hepatocytes in the experimental group was 2.18 times larger than the control group (p = 0.001). No statistically significant differences were found in capillary glucose, insulin, glucagon, IL-6, or TNF-α between two groups. Plasmatic β-hydroxybutyrate and malondialdehyde of the experimental group expressed higher levels and triglycerides lower levels compared with the control group. The results show a positive and significant correlation between the percentage of nonviable hepatocytes and malondialdehyde levels (p = 0.0217) and a statistically significant negative correlation with triglycerides levels (p = 0.006). Conclusion: Results suggest that plasmatic malondialdehyde and triglyceride levels are probably good predictors of liver damage associated with an experimental low-carbohydrate diet in rats (AU)

Introducción: varios estudios han indicado una asociación entre la modificación de la composición de macronutrientes de la dieta y la apoptosis hepática. Objetivo: el objetivo fue explicar cómo los cambios en las rutas metabólicas provoca la apoptosis hepática. Métodos: se evaluó un grupo de 17 ratas. Un grupo (n = 8) con dieta experimental: proteínas (59,46%), grasas (31,77%) e hidratos de carbono (8,77%) y otro (n = 9) con dieta control (AIN-93-M). Los animales se sacrificaron después de ocho semanas, y se pesó el tejido adiposo, se retiró el hígado para su posterior análisis por citometría de flujo, y en la sangre recogida se midieron glucosa, insulina, glucagón, IL-6, TNF, triglicéridos, malondialdehído y β-hidroxibutirato. El análisis estadístico utilizó la prueba t no pareada y paramétrica de Student, y la correlación de Pearson; significación se fi jó en p < 0,05. Resultados: no se encontraron diferencias estadísticamente significativas en la glucosa capilar, insulina, glucagón, IL-6, TNF-α o en el grupo de la dieta experimental frente al control. El β-hidroxibutirato y malondialdehído se expresaron en los niveles más altos y los triglicéridos en los niveles más bajos en el grupo experimental. El porcentaje de células no viables en el grupo de dieta experimental era 2,18 veces mayor que la del grupo control. Había menos tejido adiposo de ratas alimentadas con la dieta experimental que la dieta control. Los resultados muestran una correlación positiva y significativa entre el porcentaje de células viables y malondialdehído y una correlación negativa estadísticamente significativa con los triglicéridos. Conclusión: malondialdehído y los niveles de triglicéridos en plasma son probablemente buenos predictores de daño hepático (AU)

Apoptosis induced by a low-carbohydrate and high-protein diet in rat livers.

AIM: To determine whether high-protein, high-fat, and low-carbohydrate diets can cause lesions in rat livers. METHODS: We randomly divided 20 female Wistar rats into a control diet group and an experimental diet group. Animals in the control group received an AIN-93M diet, and animals in the experimental group received an Atkins-based diet (59.46% protein, 31.77% fat, and 8.77% carbohydrate). After 8 wk, the rats were anesthetized and exsanguinated for transaminases analysis, and their livers were removed for flow cytometry, immunohistochemistry, and light microscopy studies. We expressed the data as mean ± standard deviation (SD) assuming unpaired and parametric data; we analyzed differences using the Student's t-test. Statistical significance was set at P < 0.05. RESULTS: We found that plasma alanine aminotransferase and aspartate aminotransferase levels were significantly higher in the experimental group than in the control group. According to flow cytometry, the percentages of nonviable cells were 11.67% ± 1.12% for early apoptosis, 12.07% ± 1.11% for late apoptosis, and 7.11% ± 0.44% for non-apoptotic death in the experimental diet group and 3.73% ± 0.50% for early apoptosis, 5.67% ± 0.72% for late apoptosis, and 3.82% ± 0.28% for non-apoptotic death in the control diet group. The mean percentage of early apoptosis was higher in the experimental diet group than in the control diet group. Immunohistochemistry for autophagy was negative in both groups. Sinusoidal dilation around the central vein and small hepatocytes was only observed in the experimental diet group, and fibrosis was not identified by hematoxylin-eosin or Trichrome Masson staining in either group. CONCLUSION: Eight weeks of an experimental diet resulted in cellular and histopathological lesions in rat livers. Apoptosis was our principal finding; elevated plasma transaminases demonstrate hepatic lesions.