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Published on: December 29, 2014
[Effects of preweaning enrichment on activity-regulated cytoskeletal protein expression and long-term memory in rats]
Cheng-Qiu Lu1, Le Zhong, Ying Tian
1Shanghai Institute for Pediatric Research,Shanghai Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
Insights
Early life environmental enrichment enhances long-term memory and increases activity-regulated cytoskeletal protein (Arc) expression in young rats. This suggests enrichment positively impacts brain plasticity and cognitive function.
Area of Science:
- Neuroscience
- Developmental Psychology
- Molecular Biology
Context:
- Early life experiences significantly shape brain development and cognitive abilities.
- Environmental enrichment is a key factor influencing neural plasticity and learning.
- Understanding the molecular mechanisms underlying memory formation is crucial for addressing cognitive deficits.
Purpose:
- To investigate the impact of preweaning environmental enrichment on memory and Arc gene expression in rats.
- To determine if enriched environments enhance long-term memory formation.
- To explore the relationship between Arc expression in the hippocampus and cognitive performance.
Summary:
- Neonatal rats exposed to an enriched environment from postnatal day 10 to weaning showed improved performance in the novel object recognition test, indicating enhanced long-term memory.
- This behavioral improvement was correlated with significantly increased expression of the immediate early gene, Arc, in the CA1 and DG regions of the hippocampus.
- No significant differences in general locomotor activity were observed between control and enriched groups in the open field test.
Impact:
- Preweaning enrichment can enhance hippocampal plasticity and promote long-term memory consolidation.
- The findings highlight the role of the Arc gene as a potential molecular marker for environmental enrichment-induced cognitive benefits.
- This research provides a foundation for developing strategies to optimize cognitive development through early life interventions.
Objective:
To investigate the effects of preweaning enrichment on the expression of activity-regulated cytoskeletal protein (Arc), an immediate early gene, and on the long-term memory in rats.
Methods:
Forty neonatal Sprague-Dawley rats were randomly assigned to control group (standard environment, n=20) and experimental group (enriched environment, n=20). The experimental group received enriched environment exposure from postnatal day 10 until weaning (2 weeks, 20 minutes per day). The open field and novel object recognition tests were performed at postnatal day 28. Arc expression was detected by Western blotting and immunohistochemistry.
Results:
There was no significant difference in the open field test between the two groups. However, in the novel object recognition test, the experimental group rats performed significantly better than the control rats after 1 and 24-hr retention. The preference index in the experimental group after 1-hr (59.61%+/-9.61% vs 50.46%+/-9.34%; P<0.05) and 24-hr retention (62.72%+/-14.12% vs 52.39%+/-9.16%; P<0.05 ) was significantly higher than that in the control group. Arc expression in both areas CA1 and DG of hippocampus in the experimental group increased significantly compared with that in the control group (P<0.01).
Conclusions:
Preweaning enrichment can up-regulate the expression of immediate early gene, Arc, in the hippocampus of the rats, and promote their long-term memory.
