Cyclic Intermittent Fasting Influences the Structure of Hepatocyte Nuclear Membrane in Young and Old Rats
M. S. Girych *
Department of Molecular Biology of Ontogenesis, Research Institute of Biology, V.N. KarazinKharkiv National University, Svobody Sq. 4, 61022, Kharkiv, Ukraine.
N. I. Kurguzova
Department of Molecular Biology of Ontogenesis, Research Institute of Biology, V.N. KarazinKharkiv National University, Svobody Sq. 4, 61022, Kharkiv, Ukraine.
A. I. Bozhkov
Department of Molecular Biology of Ontogenesis, Research Institute of Biology, V.N. KarazinKharkiv National University, Svobody Sq. 4, 61022, Kharkiv, Ukraine.
*Author to whom correspondence should be addressed.
Abstract
Aims: The present study was undertaken to monitor the changes in structural and dynamic state of hepatocyte nuclear membrane of young (3-months) and old (20-months) rats subjected to intermittent fasting (IF).
Study Design: young (3-month) and old (20-month) rats were individually housed and randomly assigned to one of five groups (with 10 rats per group): (Control)-fed Ad libitum; (1IF)-provided access to a limited amount of food (4g/100g and 2g/100g of food/body weight for young and old rats, respectively) every other day for 10 days; (1R)-refeeded Ad libitum for 20 days after 1IF; (2IF)-provided the same regimen as for 1IF but after successive 1IF and 1R; (2R)-refeeded Ad libitum for 10 days after 2IF.
Methodology: The magnitude of fluidity changes was evaluated through measuring the excimer-to-monomer intensity ratio (E/M) in the pyrene emission spectra. The changes in membrane hydration were assessed using Laurdan generalized polarization (GP).
Results: During two cycles of intermittent fasting/refeeding statistically significant differences in E/M for young animals are observed only after the first refeeding (increase by 11% compared to control). 1IF and 1R in old animals were followed by ~26% and ~18% decrease in E/M value. The second cycle of dietary regimen brought about ~20% and ~36% decrease in E/M of old rats after 2IF and 1R, respectively. The first intermittent fasting resulted in ~74% and ~101% increase in GP value of young and old rats, respectively, and the refeeding period GP parameter underwent ~221% and ~89% increase in comparison with control for young and old rats, respectively. After the second IF following the first refeeding the young and old rats were characterized by ~200% and ~44% increase in GP, respectively. On the contrary, second refeeding leads to ~182% and ~27% increase in GP for young and old rats, respectively.
Conclusion: The main outcome reached is the identification of differences in the effects of re-applicated IF on nuclear membrane fluidity and hydration in animals of different age, suggesting that membrane responses to IF are governed by age-dependent mechanisms.
Keywords: Aging, nuclei membrane, membrane fluidity, membrane hydration, intermittent fasting