Hippocampal neural cell degeneration and memory deficit in high-fat diet-induced postnatal obese rats– exploring the comparable benefits of choline and DHA or environmental enrichment

Abstract

Purpose

Childhood obesity increases risk for neural dysfunctions causing learning and memory deficits. The objective of the study is to identify the effects of high fat diet-induced obesity in postnatal period on serum lipids, memory and neural cell survival in hippocampus and compare the role of choline and DHA or environmental enrichment in attenuating the alterations

Materials and methods

21 day postnatal male Sprague Dawley rats were assigned as Normal control [NC] fed normal chow diet, Obesity-induced [OB] fed high fat diet, Obesity-induced fed choline & DHA [OB + CHO + DHA], Obesity-induced environmental enrichment [OB + EE] [n = 8/group]. Memory was assessed using radial arm maze. Subsequently blood was collected for serum lipid analysis and rats were euthanized. 5 µm hippocampal sections were processed for cresyl-violet stain. Surviving neural cells were counted using 100 µm scale.

Results

Memory errors were significantly higher [p < 0.001, 0.01] in OB compared to same in NC rats. Mean number of surviving neural cells in hippocampus of OB was significantly lesser [p < 0.01] compared to same in NC. Interventions in OB + CHO + DHA and OB + EE significantly attenuated [p < 0.01] memory errors and number of surviving neural cells in hippocampus [CA1, CA3 and DG] compared to same in OB. Moreover, hippocampal neural cell survival was found to be inversely related to serum lipid profile in OB group and was attenuated in OB + CHO + DHA and OB + EE rats.

Conclusions

High fat diet-induced postnatal obesity in rats causes CA1/CA3 hippocampal neuro-degeneration and memory deficits. Supplementation of choline and DHA in obese rats attenuates these deficits.

Keywords:

• High fat diet
• Choline and DHA
• environmental enrichment
• memory
• hippocampus

Acknowledgment

Authors are grateful to Manipal Academy of Higher Education, Manipal for providing the support to conduct this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).