Nandrolone supplementation promotes AMPK activation and divergent¹⁸[FDG] PET brain connectivity in adult and aged mice

Abstract

Abnormalities in energetic and proteic homeostasis during ageing relate to neurodegenerative diseases. The mitochondria are a hub of oxidative metabolism, influencing autophagic flux. Ageing can lead to a functional disruption of these systems, leading to neuroenergetic and proteotoxic imbalance. Lower levels of testosterone have been proposed as a mechanism accelerating functional decline during ageing. In this study we investigated whether nandrolone decanoate (ND), an analog of testosterone, in aged animals improves mitochondrial bioenergetics and autophagy. Albino CF1 mice of 3 and 18 months of age, were separated in 4 groups that received daily subcutaneous injections for 15 days of either ND (15mg/kg), or vehicle. Were performed baseline and 14th day 18FDG uptake analysis, through positron emission tomography scan. High resolution respirometry was performed to assess functionally mitochondrial respiratory states and respiratory control ratio (RCR) in synaptossomes fractions. Also, hypothalamic immunocontent of AMPK, pAMPKT172, Beclin-1 and BCL-2 LC3 was assessed. Results demonstrate that aged animals did not display alterations nor in 18FDG uptake, neither in mitochondrial respiratory states. Also, aged mice displayed reduced pAMPKT172/ AMPK ratio, and increased LC3-II compared to adult controls. Curiously, ND in aged mice did neither increase 18FDG uptake, nor alter mitochondrial states. Albeit, ND increased pAMPKT172/ AMPK ratio, LC3-II turnover, as well as increased RCR. This suggest that ageing does not culminate necessarily in bioenergetics alterations in brain, although biomarkers of energetic status and autophagy are reduced. ND improved bioenergetic efficiency and autophagy in aged mice. These benefits are probably mediated by reprogramation of AMPK signalling.