Hepatocyte nuclear phenotype, the cross-talk between anabolic androgenic steroids and exercise in transgenic mice

Abstract

The growing and indiscriminate use of high doses of anabolic androgenic steroid (AAS) among youth and athletes has raised serious concerns about its hepatotoxic effects. Herein, the influence of AAS in the nuclear phenotype of hepatocytes was investigated in sedentary and trained mice heterozygous for the human CETP (cholesteryl ester transfer protein) transgene and for LDL-receptor null allele (CETP+/-LDLr+/-) by image analysis. Five groups were assayed comprising treadmill exercised (Ex) and sedentary (Sed) mice, administered mesterolone (AAS) or gum arabic (GA) and a sedentary blank control: G1(SedAAS), G2(SedGA), G3(ExAAS), G4(ExGA), and G5(SedBL). To assess nuclear phenotypes, the state of chromatin supraorganization, DNA content and fragmentation (TUNEL assay), area and perimeter of hepatocytes were determined in Feulgen-stained liver imprints. In addition, the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) hepatic transaminases were measured. SedAAS-G1 showed the lowest chromatin condensation and highest Feulgen-DNA content, polyploid nuclei frequency, nuclear area and perimeter, suggesting gene activation. Contrarily, ExAAS-G3 showed a highest chromatin condensation, and a significant decrease of Feulgen-DNA content and decreased frequency of polyploid nuclei, which suggest gene silencing. Image analysis of the nuclear phenotype offered a coherent descriptive picture of the changing patterns of chromatin organization, which were shown to be congruent with the levels of Feulgen-DNA content, geometric nuclear parameters and hepatocyte activity. In this study, the image analysis permitted the monitoring of the nuclear response to mesterolone and physical exercise action in liver cells, the molecular mechanism of which is in prospect.