Combined effects of royal jelly and environmental enrichment against stress-induced cognitive and behavioral alterations in male rats: behavioral and molecular studies

ABSTRACT

Background

Exposure to chronic stress has detrimental effects on cognitive and emotional processing. Also, the neuroprotective influences of environmental enrichment (EE) and royal jelly (RJ) have been indicated in previous studies.

Aims

To our knowledge, to date, there are no studies about the synergistic effects of EE and RJ on cognitive changes induced by stress. Therefore, this study aimed to investigate the protective effects of RJ, and EE on anxiety-like behaviors, cognitive functions, and expression of hippocampal and also prefrontal cortex (PFC) brain-derived neurotrophic factor (BDNF) levels in stressed rats.

Methods

By using restraint and cold temperature, rats were exposed to stressful situations and then subjected to treatment with RJ or/ and EE for 14 days. Stress induction was done 14 days before treatments by placing the rats in the restrainer under 4°C. Following the interventions, anxiety-like behaviors, novel object recognition memory (NORM), inhibitive avoidance performance, hippocampal, and PFC BDNF expression were examined. The plasma corticosterone level of all groups was also evaluated.

Results

Results showed increased plasma corticosterone levels, stress-induced deficits in the NORM and IA tests, and increased anxiety-like behaviors. EE and RJ improved these deficits with a decline in serum corticosterone and also increased BDNF levels in the hippocampus and PFC in stressed ones.

Conclusion

The EE and the RJ prevented the detrimental effects of stress on anxiety-like behaviors and memory processes. These treatments can protect susceptible brain areas against chronic stress via improvement in behavioral and cognitive impairments through mediating BDNF expression.

GRAPHICAL ABSTRACT

KEYWORDS:

• Chronic stress
• environmental enrichment
• cognition
• BDNF
• Royal Jelly
• corticosterone
• prefrontal cortex
• hippocampus

Disclosure statement

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

Data availability statement

Data or information on the data can be accessed when requested.

Additional information

Funding

This work was supported by Ardabil University of Medical Sciences [Grant Number 127].

Notes on contributors

Amir Mohammad Ghorbanpour

Amir-Mohammad ghorbanpour is pharmacy student in Ardabil University of Medical Sciences and his research interests lie in the area of pharmacology and molecular theqniques (westren blotting).

Meysam Saboor

Meysam Saboor is pharmacy student in Ardabil University of Medical Sciences and his research interests lie in the area of pharmacology.

Reza Panahizadeh

Reza Panahizadeh is medical student in Ardabil University of Medical Sciences and his research interests lie in the area of medicine.

Hakimeh Saadati

Hakimeh Saadati is assistant professor of neuroscience in School of Medicine and Allied Medical Sciences & Pharmaceutical Sciences Research Center, Ardabil University of Medical Sciences. She completed his Ph.D. at Kerman University of Medical Sciences (Iran). Her research interests lie in the area of neuroscience.

Masoomeh Dadkhah

Masoomeh Dadkhah is Research Assistant Professor of Physiology Pharmaceutical Sciences Research Center, Ardabil University of Medical Sciences. She completed his Ph.D. at Semnan University of Medical Sciences (Iran). Her research interests lie in the area of behavioral neuroscience, learning & memory, stress, and fear memory extinction.