Neurocalcin-delta: a potential memory-related factor in hippocampus of obese rats induced by high-fat diet.

Wei-Wei Ma1, Bing-Jie Ding2, Lin-Hong Yuan1, Lei Zhao3, Huan-Ling Yu1, Yuan-di Xi1, Rong Xiao1
1. School of Public Health, Beijing Key Laboratory of Enviromental Toxicology, Capital Medical
University, Beijing 100069, China.
2. Department of Clinical Nutrition Beijing Friendship Hospital, Capital Medical University.
3. Department of Molecular Physiology and Biophysics, Holden Comprehensive Cancer Center,
University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA

Abstract
Introduction: Aberrant protein expression within the hippocampus has recently been implicated in the pathogenesis of obesity-induced memory impairment.

Objectives: The objective of the current study was to search for specifc memory-related factors in the hippocampus in obese
rats.

Methods: Sprague-Dawley (SD) rats were fed either a high-fat (HF) diet or normal-fat (NF) diet for 10 weeks to obtain the control (CON), diet-induced obese rats (DIO) and diet-resistant (DR) rats. D-galactose was injected subcutaneously for 10 weeks to establish model (MOD) rats with learning and memory impairment. After the hippocampus of the rats sampling, the proteome analysis was conducted using two-dimensional get electrophoresis (2-DE) combined with peptide mass fngerprinting (PMF).

Results: We found 15 differential proteins that expressed in the hippocampus in rats induced by HF diet from the 2-DE map.
In addition, Neurocalcin-delta (NCALD) was nearly down-regulated in the DR rats compared with CON rats and MOD rats, which was further confrmed by Western blot, real-time PCR and ELISA results.

Conclusion: Our data demonstrates that the differential memory-related proteins were a reflection of the HF diet, but not potential factors in obesity proneness or obesity resistance. Furthermore, NCALD is proved to be a potential hippocampus-memory related factor related to obesity.

Keywords: Diet-induced obesity; diet-resistant; high fat diet; neurocalcin-delta; proteome.