A behavioral and molecular study; ameliorated anxiety‐like behavior and cognitive dysfunction in a rat model of chronic unpredictable stress treated with oregano extract

Abstract

Objective Chronic stress is considered a severe risk factor leading to various disorders, including anxiety and cognitive decline. The present study aimed to investigate the effects of Origanum vulgare (oregano) extract on improving anxiety‐like behavior and learning and memory defection caused by chronic unpredictable stress (CUS). Method A 10‐day CUS protocol was executed on male rats, and on day 10, their anxiety, learning, and memory status were evaluated. After that, in addition to the CUS, the rats were treated with the oregano extract for 2 weeks. Then, the expression of BDNF, TrkB, and TLR2/4 genes in the hippocampus and prefrontal cortex of the rats was evaluated. Also, the liver‐ and kidney‐related serum parameters, including triglycerides, total cholesterol, HDL, LDL, creatinine, urea, serum glucose, alanine aminotransferase, and aspartate aminotransferase were assessed. Further, the extract's lethal effect and its impact on animals’ body weight were investigated. Results Behavioral tests confirmed the anxiety‐like behavior and learning–memory function impairment caused by CUS. In contrast, the administration of the extract could significantly alleviate the mental deficiencies and diminished anxiety‐like behaviors. Molecular assessments showed that CUS could markedly decrease the BDNF and TrkB genes’ expression levels while increasing that of TLR2 and TLR4. In contrast, in extract‐treated animals, mRNA levels of BDNF and TrkB considerably increased, yet TLR2 and TLR4 mRNA levels reduced. Additionally, consumption of the extract caused weight gain, while having no lethality and detrimental effect on the liver and kidneys functions. Conclusions These findings indicate the anxiolytic properties of the extract and its improving effect on cognitive dysfunction.

Methyl jasmonate ameliorates pain‐induced learning and memory impairments through regulating the expression of genes involved in neuroinflammation

“…Increasing the oxidative markers can also induce inflammation and interrupt neurobehavioral functions, such as learning and memory (Bhatt et al., 2018 ; Khorrami et al., 2023 ; Mohseni‐Moghaddam et al., 2022 ). However, antioxidant agents owing to their free radical scavenging properties can ameliorate cognitive impairments and pain‐trigger sensitivity toward neuroinflammatory conditions (Kaur et al., 2020 ; Khorrami et al., 2019 ).…”